7.1 - 7.5 Cryptography and PKI

Certificate Process

For an organization to get a certificate, it submits a certificate signing request (CSR). Once the CSR has been submitted to the certificate authority, the certificate authority validates the information and issues the certificate. Sometimes, the certificate authority may rely on a third party to perform the validation. These third parties are called registration authorities (RA). The RA is certified by a root certificate authority and is authorized to issue certificates for specific uses only. This request generally includes the following information:

You are concerned that if a private key is lost, all documents encrypted with your private key will be inaccessible. Which service should you use to solve this problem?

Key escrow Key escrow backs up private keys to a third-party organization outside of the company. If the private key is lost, you can recover the key from escrow. Online Certificate Status Protocol (OCSP) is a protocol used to check the status of an individual digital certificate to verify whether it is good or has been revoked. A Cryptographic Service Provider (CSP) resides on the client and generates the key pair. A registration authority (RA) verifies the information included in a certificate request.

Key escrow

Key escrow is a common method of key archival. With this method, keys are sent to a trusted 3rd party instead of a CA. This is often done for security and legal purposes. Legal action might be required to access the keys. This is done by design to ensure security and safety of the keys.

Which of the following are true of Triple DES (3DES)?

Key length is 168 bits Triple DES: > Applies DES three times > Uses a 168-bit key Advanced Encryption Standard (AES) uses the Rijndael block cipher. DES can easily be broken. International Data Encryption Algorithm (IDEA) uses 64-bit blocks with 128-bit keys.

Dictionary

A dictionary attack is a type of brute-force attack. The hacker uses a list of words and phrases to try to guess the decryption key. > Dictionary attacks work well if weak passwords are used. > Using longer and uncommon passphrases is the best way to secure data against these attacks.

Digital signature

A digital signature is a combination of asymmetric encryption and hashing values. A signature provides confidentiality, integrity validation, strong authentication, and non-repudiation.

Speed

Speed is one of the biggest limitations of encryption. The encryption process can take a long time, especially with the large file sizes in use today. For example, BitLocker encrypts 500 megabytes in approximately 1 minute. A 2TB drive would take approximately 67 hours to encrypt.

State/county/region

State where the organization is located. This should not be abbreviated. Example: Utah

Bridge model

The bridge model is a hybrid model that connects the hierarchical models of two organizations. > Clients in both organizations will trust certificates issued by CAs of either organization. > Trusts can be setup further down the tree for deeper customization and security.

7.1.7 Cryptography Algorithms Facts

The cornerstone of all cryptography is the algorithm, or cipher. There are different types of ciphers in use today. This lesson covers the following topics: > Stream cipher > Block cipher > Lightweight cryptography > Homomorphic encryption

Email address

The email address for the person managing the certificate in the organization. Example: [email protected]

Ciphertext

The encrypted form of a message that is readable only by those for whom the message is intended.

Organization Validation

The organization validation is one step up from the domain validation. With organization validation: > The purchaser needs to prove they are a domain administrator and also prove the organization is legitimate. > The validation process includes proving the organization is real and some basic information. But it is not as in depth as the extended validation. > These certificates can be issued in 1-3 days.

Steganography

The practice of concealing a file, message, image, or video within another file, message, image, or video.

Which of the following would require that a certificate be placed on the CRL?

The private key is compromised. Certificates are published to the Certificate Revocation List (CRL) when a condition compromises the integrity of the certificate. If the private key is compromised (discovered), the certificate is no longer proof of identity. Certificates do not need to be placed on the CRL if their validity period expires. In this case, the certificate simply expires. Knowing the signature key size or the encryption key algorithm does not compromise the integrity of the certificate.

Decryption

The process of converting data from ciphertext into plaintext.

Encryption

The process of using an algorithm or cipher to transform data from cleartext to ciphertext in order to protect the confidentiality, integrity, and authenticity of the message.

Hashing

The process of using an algorithm to convert data to a fixed-length key called a hash.

Deterministic

The same data always generates the same hash.

X.509

The standard that defines the format of certificates.

Country

The two-letter code for the country where the organization is located. Example: US

Cryptography Methods

There are many different cryptography methods used today. One important thing to keep in mind is that all cryptography uses advanced math concepts to generate encryption keys and hashes.

Cryptography Concepts

There are three main concepts to understand when dealing with today's encryption methods: encryption keys, hashing, and digital signatures.

Common name

The fully qualified domain name (FQDN) of the website. Example: www.testout.com

Root Certificate

A root certificate is the first certificate that a Certificate Authority creates. Root certificates are: > Self-signed certificates. These certificates go through a different validation process which varies depending on the certificate and organization. > Used to sign lower-level certificates such as intermediate certificates.

Subject alternative name (SAN)

An optional field. The SAN allows the organization to have multiple host names covered in one certificate. Example: site1.testout.com and site2.testout.com

Hashing Uses

Hashing is often used for the following:

Public key infrastructure (PKI)

PKI is an environment in which public encryption keys can be created and managed throughout the key lifecycle.

Collision resistant

Two different pieces of data should not generate the same hash.

Blockchain

A decentralized and distributed ledger of transactions between two or more parties. Blockchain uses cryptography to keep sensitive data secure.

Digital signature

Hashes are a critical piece of a digital signature. The creator combines a hash of the data along with their private key to generate the digital signature.

7.2.5 Cryptographic Implementation Facts

> This lesson covers the following topics: - Hybrid models - Digital signatures - Encryption with steganography - Hardware-based encryption

Hardware Security Module (HSM)

A Hardware Security Module (HSM) is a piece of hardware and associated software/firmware that is connected to a computer system to provide cryptographic functions such as: > Generate and store encryption keys > Generate and validate digital signatures > Generate keys used in smart cards HSMs traditionally come in the form of a plug-in card or an external security device that can be attached directly to the computer system. These devices offer some benefits over TPM chips. > HSMs are more powerful and can perform more powerful cryptographic functions quicker. > HSMs can perform multiple cryptographic functions simultaneously. > HSMs can be attached to a network and handle cryptographic functions for multiple users across the network. Hardware Security Modules are also known as: > Personal Computer Security Module (PCSM) > Secure Application Module (SAM) > Hardware cryptographic devices > Cryptographic modules

Trust model

A PKI uses a trust model to establish trust between two communicating entities. Depending on the number of CAs being implemented and the use, there are a few configurations that can be used to setup certificate authorities.

Certificate Revocation List Management

A certificate revocation list contains a list of digital certificates that have been revoked by the issuing certificate authority before their scheduled expiration date and should no longer be trusted. If the root CA is taken offline, it can no longer maintain the CRL. The following table describes other methods that can be used to keep track of these revoked certificates:

Digital Signature

A digital signature is a combination of asymmetric encryption and hashing values. A signature provides confidentiality, integrity validation, strong authentication, and non-repudiation. Typically, a digital signature works as follows: 1. A hash value is generated for a message. 2. The hash value is asymmetrically encrypted using the sender's private key. Non-repudiation is provided because only the sender could have encrypted the hash using the private key (only the sender knows the private key). 3. The encrypted hash value and the message are sent. 4. The recipient decrypts the hash using the sender's public key. 5. The recipient hashes the message. 6. Message integrity and sender authenticity (non-repudiation) is confirmed if the two hash values match.

Hash

A function that converts a variable-length string into a compressed, fixed-length value known as a message digest or hash.

Hash collision

A hash collision occurs when two files generate the same hash.

Hierarchical model

A hierarchical model looks like a tree. > The first CA created is the root CA. It is a self-signed certificate and is used to validate additional subordinate CAs. > The subordinate CAs are known as intermediate CAs. The intermediate CAs validate issuing CAs. > Issuing CAs validate and distribute the certificates.

File Encryption Key (FEK)

A pseudo-random number used with the AES encryption algorithm to encrypt files and folders in EFS.

Rainbow table

A rainbow table is a table of passwords and their generated hashes.

Data Decryption Field (DDF)

A special location in a EFS encrypted file's header that stores the FEK.

Web of trust

A web of trust is typically used with Pretty Good Privacy encryption (PGP). Instead of implementing a CA, everyone is considered a trusted authority. For example, if User1 trusts User2 and User2 trusts User3, User1 will also trust User3.

Advanced Encryption Standard (AES)

AES, also known as the Rijndael cipher, was developed by Jaon Daemen and Vincent Rijmen in 2001 as part of a NIST competition held to find a replacement for DES. > AES has essentially replaced all other types of symmetric encryption. > AES offers three different key lengths of 128, 192, and 256 bits. > AES is used in many different applications including 802.11 communications, Bitlocker, and even game engines.

A private key has been stolen. Which action should you take to deal with this crisis?

Add the digital certificate to the CRL If a private key--a digital certificate or digital signature--is compromised (especially by theft), it should be added to the CRL. This prevents any future use of the key/certificate and prevents impersonation attacks. There is no need to delete the public key because CRLs deal with any attempted use of the private key. The private key should have been placed in escrow at the beginning of its lifetime if key recovery was desired. In this situation, key recovery is not necessary.

Single trust model

All CAs start with a single trust model. This is the simplest model to setup. The single trust model has the following characteristics: > There is only one CA that issues and distributes certificates. > All users trust the CA and there are no trusts established with other CAs. > This model works properly only in a small organization. > If the CA is compromised, all certificates must be replaced.

Galois Counter Mode (GCM)

All other modes of operation are unauthenticated forms of encryption. The Galois Counter Mode provides both encryption and authentication. > GCM works just like Counter Mode except the ciphertext is combined with a special hash. > The output of the ciphertext and hash contains the encrypted data along with a Message Authentication Code (MAC) that gives assurance the message has not been tampered with. > Because GCM is extremely efficient and provides authentication, it is often used with network communications such as 802.11 and when sending encrypted data to a web server using TLS or SSH. > There are other encryption methods that also provide authentication, but GCM is the most widely used method.

Homomorphic Encryption

An inherent risk with all encryption is that for the data to be worked on (computation on ciphertexts), it must first be decrypted. Homomorphic encryption addresses this concern by allowing data to be worked on without decrypting it first. There are three types of homomorphic encryption. To explain the differences, it works best to think of data as integers and to use math functions to represent the manipulation of that data.

Intermediate CA

An organization can choose to setup and configure an intermediate CA whose sole purpose is to maintain and update the CRL.

Authenticity

Applying a digital signature proves that the file is authentic and comes from the correct person.

Non-repudiation

Applying a digital signature provides non-repudiation. This means that the sender cannot later deny having sent the file.

7.5 Public Key Infrastructure

As you study this section, answer the following questions: > What is the lifecycle of an encryption key? > What is the role of a certificate authority (CA)? > What are the types of certificates? > Which standard defines the format of certificates? > Which trust model would be used to connect the CAs of two organization's? In this section, you will learn to: > Manage certificates.

7.3 Hashing

As you study this section, answer the following questions: > What is the output of hashing called? > What are the five characteristics of a hash function? > What are some common uses for hashing? > What type of attack takes advantage of hash collisions? > What are the main hashing algorithms used? In this section, you will learn to: > Use hashes. > Compare MD5 hashes.

7.4 File Encryption

As you study this section, answer the following questions: > Which editions of Windows include Encrypting File System (EFS)? > Why would you create a Data Recovery Agent (DRA)? > Which standard does Pretty Good Privacy (PGP) and GNU Privacy Guard (GPG) follow? > What partition/volumes are created when implementing BitLocker? > What are three methods of database encryption? In this section, you will learn to: > Encrypt files using EFS. > Encrypt files using GPG. > Configure BitLocker with a Trusted Platform Module (TPM).

A PKI is an implementation for managing which type of encryption?

Asymmetric A public key infrastructure (PKI) is a hierarchy of computers that issue and manage certificates. Certificates use asymmetric encryption with a public and private key pair.

7.5.2 Public Key Infrastructure Facts

Asymmetric encryption methods, which use a public key to provide confidentiality and trust, are generally used to encrypt data transmitted over the internet. Proper management and safety of these keys is important. Public key infrastructure (PKI) provides an environment in which public encryption keys can be created and managed. At the heart of PKI are certificate authorities (CAs) who are responsible for issuing, validating, and revoking certificates. This lesson covers the following topics: > Certificate authorities. > Certificate process. > Certificate attributes.

7.4.3 Encrypt Files with EFS Lab

At work, you share a computer with other users. You want to secure the contents of the Finances folder so that unauthorized users cannot view its contents. In this lab, your task is to: > Encrypt the D:\Finances folder and all of its contents. > Add the Susan user account as an authorized user for the D:\Finances\2020report.xls file. Complete this lab as follows: 1. Open the D: drive. a. From the Windows taskbar, select File Explorer. b. From the left pane, select This PC. c. From the right pane, double-click Data (D:). 2. Encrypt the Finances folder. a. Right-click Finances and then select Properties. b. Select Advanced. c. Select Encrypt contents to secure data and then select OK. d. Select OK to close the properties dialog. e. Select OK to confirm the attribute changes. 3. Give Susan authorization to modify the 2020report.xls file. a. Double-click Finances. b. Right-click 2020report.xls and then select Properties. c. Select Advanced. d. Select Details. e. Select Add. f. Select Susan and then select OK. g. Select OK as many times as needed to close all remaining dialogs.

Availability

Availability of data is one of the goals of Information Security. Since encryption can hinder the availability of data, it is important to measure the level of security against the availability of a resource. The more secure data is made, the more difficult (less available) it becomes for a user to access.

Public key

Before filling out the CSR, the organization needs to generate a key pair. The public key will be included here.

You want a security solution that protects the entire hard drive and prevents access even if the drive is moved to another system. Which solution should you choose?

BitLocker BitLocker is a Microsoft security solution that encrypts the entire contents of a hard drive, protecting all files on the disk. BitLocker uses a special key that is required to unlock the hard disk. You cannot unlock/decrypt a drive simply by moving it to another computer. EFS is a Windows file encryption option, but it only encrypts individual files. Encryption and decryption is automatic and dependent upon the file's creator and whether other uses have read permissions. A virtual private network (VPN) uses an encryption protocol (such as IPsec, PPTP, or L2TP) to establish a secure communication channel between two hosts or between one site and another site. Data that passes through the unsecured network is encrypted and protected.

BitLocker

BitLocker is used to encrypt an entire volume. All data on the volume is protected even if the hard drive is moved to another computer.

TPM chip

BitLocker utilizes the computer's Trusted Platform Module (TPM) chip. The TPM chip is built onto the motherboard and generates and stores encryption keys to protect boot files. If the hard drive is moved to another computer, the encryption keys won't match and the data on the drive cannot be accessed. (The TPM chip must be at least version 1.2 for BitLocker to use it.) BitLocker can be enabled without a TPM chip, but boot files will not be encrypted. To use BitLocker without the TPM chip, the user will need to use a startup USB key or have a system volume password enabled to boot into Windows. This option is enabled through the following policy: Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives

BitLocker

BitLocker was introduced in Windows Vista and is used to encrypt an entire volume, not just individual files and folders. BitLocker is designed to protect all data on a volume even if the hard drive is moved to another computer.

You've used BitLocker to implement full volume encryption on a notebook system. The notebook motherboard does not have a TPM chip, so you've used an external USB flash drive to store the BitLocker startup key. You use EFS to encrypt the C:\Secrets folder and its contents. Which of the following is true in this scenario? (Select two.)

By default, only the user who encrypted the C:\Secrets\confidential.docx file will be able to open it. If the C:\Secrets\confidential.docx file is copied to an external USB flash drive, the file will be saved in an unencrypted state. BitLocker uses full volume encryption, while EFS is used to encrypt individual files and folders. The following are true in this scenario: > If the C:\Secrets\confidential.docx file is copied to an external USB flash drive, the file will be saved in an unencrypted state. > Only the user who encrypted the C:\Secrets\confidential.docx file will be able to open it by default. With BitLocker enabled, any user who has the appropriate startup key or PIN is able to boot the system from the encrypted drive. However, only the user who encrypted the C:\Secrets\ folder will be able to access files within it unless additional user accounts are explicitly added.

Code Signing Certificate

Code-signing certificates are used by app developers to prove that their application is legitimate. If a user tries to run an app that does not have a certificate, they will receive an error stating that the app cannot be trusted. The user can decide to close the app or run

City/locality

City where the organization is located. Example: Pleasant Grove

CAST

CAST is a family of ciphers that now consists of CAST-128 (CAST5) and CAST-256 (CAST6). > CAST5 is the most widely used CAST cipher. It replaced IDEA in PGP 3.0 and is also an option in all versions of Open PGP. > CAST6 was entered in the AES competition but was not a finalist.

7.1.14 Section Quiz

CIST 1601

7.2.6 Section Quiz

CIST 1601

7.3.6 Section Quiz

CIST 1601

7.4.10 Section Quiz

CIST 1601

7.5.11 Section Quiz

CIST 1601

Certificate Chaining

Certificate authorities are generally setup in a hierarchy of multiple CAs to increase security. > The first CA created is the root CA. The certificate is self-signed and is used to validate additional subordinate CAs. > The subordinate CAs are known as intermediate CAs. These CAs validate issuing CAs > Issuing CAs validate and distribute the certificates. This structure is known as certificate chaining or the Chain of Trust. It is commonly used to protect the root CA. For example, if the root CA is compromised, then all the certificates issued by that CA would need to be replaced. By implementing certificate chaining, if a CA is compromised, only the certificates issued by that CA would need to be replace. Another common method of protecting the root CA is to bring it online only when it needs to authorize a new intermediate CA. Being offline means the root CA is isolated from all network access and is usually turned off.

Certificate authorities

Certificate authorities are reputable organizations that are responsible for issuing public certificates to companies or organizations that want to securely communicate over the internet.

Certificate Authorities

Certificate authorities are reputable organizations, responsible for issuing public certificates to other companies or organizations for secure communication over the internet. Certificate authorities are generally set up in a hierarchy of multiple CAs to increase security. This is also known as certificate chaining. CAs are usually set up as follows: > The first CA created is the root CA. The root CA has a self-signed certificate which is used to validate additional subordinate CAs. > The subordinate CAs are known as intermediate CAs. These CAs validate issuing CAs. > Issuing CAs validate and distribute the certificates. The follow graphics depicts the CA hierarchy. This structure is commonly used to protect the root CA. If the root CA is ever compromised, all issued certificates must be replaced. By implementing certificate chaining, only certificates issued by the compromised CA need to be replaced.

Certificate chaining

Certificate authorities are usually setup in a hierarchy of multiple CAs to increase security. This structure is known as certificate chaining or the chain of trust.

Avalanche effect

Changing any bit of data will result in a completely different hash.

When two different messages produce the same hash value, what has occurred?

Collision A collision occurs when two different messages produce the same hash value. A birthday attack is a brute force attack in which the attacker hashes messages until one with the same hash is found. A hash value is the result of a compressed and transformed message (or some type of data) into a fixed-length value. High amplification means a small change in the message results in a big change in the hashed value.

Column-level encryption

Column-level encryption allows the administrator to encrypt each column separately. > Each column is encrypted using a different key, which increases security. > Column-level encryption causes a hit to the performance of the database.

You create a new document and save it to a hard drive on a file server on your company's network. Then you employ an encryption tool to encrypt the file using AES. This activity is an example of accomplishing which security goal?

Confidentiality Encrypting a file while it is stored on a hard drive is usually done to provide protection for the object's confidentiality. Hashing is used to provide integrity. Using mechanisms like backups and avoiding single points of failure provide availability protection. Non-repudiation is usually provided for during a secured communication, not while a file is stored on a hard drive.

Which of the following functions are performed by a TPM?

Create a hash of system components A Trusted Platform Module (TPM) is a hardware cryptoprocessor that resides on the motherboard. This hardware is used to store and generate cryptographic keys. The TPM also generates hash values of system components. The hash value verifies that startup components have not been modified. Because each system has a unique hash value, the hash can also be used as a form of identification for the system. Keys generated by the TPM are used for encryption and authentication, but the TPM does not perform the actual encryption. A smart card is a hardware device containing a digital certificate. The smart card can be used for authentication. Special hardware processors perform bulk encryption in hardware rather than software. These processors typically encrypt data using AES or encrypt network traffic using IPsec.

Hashing algorithms are used to perform which of the following activities?

Create a message digest. Hashing algorithms are used to create a message digest to ensure that data integrity is maintained. A sender creates a message digest by performing the hash function on the data files that are transmitted. The receiver performs the same action on the data received and compares the two message digests. If they are the same, the data was not altered. Symmetric algorithms are used to encrypt bulk data for communications exchange. Asymmetric algorithms provide a means for exchanging small amounts of data securely over a public network. Both symmetric and asymmetric algorithms provide non-repudiation.

Integrity

Creating a hash of a file can be used to validate that the file has not been altered. This validates the integrity of the file.

Which of the following should you set up to ensure encrypted files can still be decrypted if the original user account becomes corrupted?

DRA If a user account becomes corrupted or the password is forgotten, any encrypted files are lost. To help remedy this, a data recovery agent (DRA) can be set up. The DRA is simply another account that can decrypt the encrypted files. Pretty Good Privacy (PGP) is an older utility used to encrypt and decrypt data and messages. A virtual private network (VPN) uses an encryption protocol (such as IPsec, PPTP, or L2TP) to establish a secure communication channel between two hosts or between one site and another site. GNU Privacy Guard (GPG) is a command line utility that's used to encrypt and decrypt data and messages.

Certificate Types

Depending on the use and situation, there are different types of public key infrastructure (PKI) certificates. The following table explains what these certificate types are and how they can be used:

Hashing Algorithms

Depending on the use, there are different hashing algorithms which can be used.

Which of the following is a direct integrity protection?

Digital signature A digital signature is a direct integrity protection. It includes the use of hashing, which detects changes to integrity. Digital envelopes, symmetric encryption, and asymmetric encryption do not provide direct integrity protection, nor do they use hashing to provide integrity protection.

What is the most obvious means of providing non-repudiation in a cryptography system?

Digital signatures Digital signatures, which are private keys from an asymmetric cryptographic system, are the most obvious means of providing non-repudiation. Only a single person is in possession of their private key. If a message is found with their digital signature, they are the only user who could possibly have created and transmitted it. Public keys are useful for restricting delivery, such as using them as digital envelopes, but they don't provide non-repudiation. Hashing values protect integrity, but they don't provide non-repudiation. Shared secret keys do not provide true non-repudiation because two entities hold copies of the shared key.

Distinguished Encoding Rules

Distinguished encoding rules (DER), is one of the older formats used. DER characteristics are: > DER is a set of rules that defines how data must be encoded in a file. > DER is defined by the ASN.1 standard. > DER is a binary (non-text) encoding format. > DER is mainly used in Windows systems. > DER certificates usually have a .der or .cer file extension.

Domain Validation

Domain validation is the lowest level of validation. With domain validation: > A CA issues a domain-validated certificate to anyone listed as an administrator on the WHOIS record. > Validation generally consists of a phone call or email. > Certificates are usually issued within minutes.

Data recovery

During the process of enabling BitLocker, Windows generates the recovery key. The recovery key is different from the user-generated password that is created during the setup process. This is a randomly generated key that can be used to recover data in the following instances: > Moving the hard drive to a new system > Changes are made to startup files > BitLocker goes into a locked state The recovery key is extremely important and should be backed up in multiple places. BitLocker gives the following options to back up the key: > Personal Microsoft Account > USB flash drive > File (the file cannot be saved to an encrypted drive) > Print the key out > If the computer is on an Active Directory network, the recovery key can be saved in Active Directory A special user account called the data recovery agent (DRA) can be created and can decrypt any encrypted data drive on the network. If the hard drive contains the operating system files, it will need to be installed on another system as a data drive before the DRA can decrypt it.

Which of the following security solutions would prevent a user from reading a file that she did not create?

EFS EFS is a Windows file encryption option that encrypts individual files so that only the user who created the file can open it. Decryption is automatic when the file owner opens it. Other users cannot open the encrypted file unless specifically authorized. BitLocker is a Microsoft security solution that encrypts the entire contents of a hard drive, protecting all files on the disk. BitLocker uses a special key that is required to unlock the hard disk. You cannot unlock/decrypt a drive simply by moving it to another computer. A virtual private network (VPN) uses an encryption protocol (such as IPsec, PPTP, or L2TP) to establish a secure communication channel between two hosts or between one site and another site. Data that passes through the unsecured network is encrypted and protected.

Encrypting File System

EFS provides a easy and seamless way for users to encrypt files on Windows computers. EFS is used to encrypt only individual files and folders.

Certificate Attributes

Each CA has the responsibility of maintaining a database that contains the information, or attributes, of each certificate. The attributes that can be included are: > Version - The X.509 version used for the certificate. > Serial Number - A unique identifier for each certificate. > Signature algorithm - The algorithm used to sign the certificate (SHA-2, RSA, etc.). > Issuer - The CA that issues the certificate. > Valid From and Valid To - The two fields that show the validity period of the certificate. > Subject - The field that contains the name and location information of the organization. > Public Key - The algorithm used to create the key and the public key information. Depending on the organization, there may also be additional optional fields called extensions in the certificate. One of the key attributes is the Valid To field. If a certificate is not renewed by this date, it will expire and no longer be valid. Aside from expiration, some other reasons a certificate might be invalidated are: > The organization no longer exists. > The private key has been compromised. > The issued certificate is discovered to be fake. If a certificate is invalidated for these or other reasons, it will be added to a certificate revocation list (CRL). The CRL is a blacklist of certificates. CAs must maintain and constantly update the CRLs as part of their databases. Web browsers automatically download updated CRLs at set intervals. The X.509 standard also defines an internet protocol which can be used to determine the validity or state of a certificate. This is called the Online Certificate Status Protocol (OCSP). OCSP can be used to simplify the process of checking whether or not a certificate is valid. OCSP is designed to replace CRLs. Instead of a CA maintaining the CRL, an OCSP server called a responder maintains the lists of any revoked certificate. When the browser connects to a site, the browser sends a request to the OCSP responder to check the validity of the certificate. OCSP provides the following benefits: > Timely information on the status of a certificate. > Better bandwidth management because the client does not download the entire CRL. > A grace period for expired certificates.

You would like to implement BitLocker to encrypt data on a hard disk, even if it is moved to another system. You want the system to boot automatically without providing a startup key on an external USB device. What should you do?

Enable the TPM in the BIOS. When a system boots, the startup key is required to unlock the encrypted volume. The system startup key can be saved in the Trusted Platform Module (TPM). With the startup key saved in the TPM, the system can start without additional intervention. The system will not start without the startup key. Without a TPM, the startup key must be stored on a USB drive. You can require a PIN in addition to a startup key, but the PIN cannot replace the startup key. Storing the startup key on the boot drive would expose it to compromise.

7.4.9 File Encryption Facts

Encryption of files, directories, and hard drives provides an additional level of data security. File encryption is part of a layered defense strategy and helps to protect confidential data in the event that system data is hacked, lost, or stolen. There are different methods that can be used to encrypt data or entire hard drives. This lesson covers the following topics: > Encrypting File System (EFS) > PGP and GPG > BitLocker > Database encryption

Extended Validation

Extended validation is the highest level of validation offered by a CA. With extended validation: > The purchaser needs to prove they are a domain administrator and the CA will also validate all information on the organization. > The CA will validate using a thorough and standardized identity verification process. This process includes proving: - Exclusive rights to the domain - The organization's legal, physical, and operational existence - The organization has authorized the issuance of the certificate > These certificate can take up to 5 days to be issued.

PGP and GPG

GNU Privacy Guard (GPG) is an encryption tool that encrypts emails, digitally signs emails, and encrypts documents. GPG is an implementation of the Pretty Good Privacy (PGP) Protocol. PGP is a commercial product that is now owned by Symantec and makes products that can be used to protect laptops, desktops, USB drives, optical media, and smartphones. Both PGP and GPG do the following: > Follow the OpenPGP standard (RFC 4880) for encrypting and decrypting data. > Combine asymmetric and symmetric cryptography. The process is as follows: 1. GPG/PGP generates a random symmetric key and uses it to encrypt the message. 2. The symmetric key is then encrypted using the receiver's public key and sent along with the message. 3. When the recipient receives a message, GPG/PGP first decrypts the symmetric key with the recipient's private key. 4. The decrypted symmetric key is then used to decrypt the rest of the message. GPG supports many common algorithms including RSA, DSA, 3DES, IDEA, MD5, SHA, and more. AES is used by default. PGP can use either RSA or the Diffie-Hellman algorithm for asymmetric encryption and IDEA for symmetric encryption.

Which utility would you MOST likely use on OS X to encrypt and decrypt data and messages?

GPG GNU Privacy Guard (GPG) is a command line utility that's used to encrypt and decrypt data and messages. GPG is a open source utility and can be used on many different systems, including Windows, Linux, Android, and Apple's OS X. Pretty Good Privacy (PGP) is an older utility used to encrypt and decrypt data and messages. PGP was purchased a while ago and commercialized. It's owned by NortonLifeLock, formally known as Symantec, and provides products that can protect all sorts of devices, even smartphones. While PGP can be used on OS X, GPG is used by default. A virtual private network (VPN) uses an encryption protocol (such as IPsec, PPTP, or L2TP) to establish a secure communication channel between two hosts or between one site and another site. A VPN is not used on OS X to encrypt and decrypt data and messages. IPSec is a protocol used to encrypt VPN communication.

GNU Privacy Guard

GPG is an encryption tool that encrypts emails, digitally signs emails, and encrypts documents.

What is the main function of a TPM hardware chip?

Generate and store cryptographic keys A Trusted Platform Module (TPM) is a hardware cryptoprocessor that resides on the motherboard. This hardware is used to store and generate cryptographic keys. These keys are used for encryption and authentication, but the TPM does not perform the actual encryption. A smart card is a hardware device containing a digital certificate. The smart card can be used for authentication. Special hardware processors perform bulk encryption in hardware rather than software. These processors typically encrypt data using AES or encrypt network traffic using IPsec.

Quick and efficient

Generating the hash should be quick and not use too many resources. The hash should also be generated using the entire message or data, not just a small piece of it.

Which of the following is a message authentication code that allows a user to verify that a file or message is legitimate?

HMAC Hash-Based Message Authentication Code (HMAC) is a type of message authentication code. Like a digital signature, HMAC allows a user to verify that a file or message is legitimate. SHA is a family of hashes that is used in many different security protocols. MD5 was developed in 1991 and is no longer viable for security purposes. RIPEMD is a family of cryptographic hash functions that was first developed in 1992 as part of the EU's RIPE project.

Hash-Based Message Authentication Code (HMAC)

HMAC is a type of message authentication code. Like a digital signature, HMAC allows a user to verify that a file or message is legitimate. > The message sender provides a secret key that is used with a hash function, such as MD5 or SHA, to create a message authentication code. > The recipient then uses the key to verify both the integrity and authenticity of the message.

Hardware-Based Encryption

Hardware devices can be combined with software-based encryption to offer powerful cryptography options. The following table shows the two most common hardware cryptography devices - TPM and HSM.

Which of the following is used to verify that a downloaded file has not been altered?

Hash A hash is a function that takes a variable-length string (message) and compresses and transforms it into a fixed-length value. Hashes ensure the data integrity of files and messages in transit. For example, when users post files for download, they often create a hash value for the file. After you download the file, you can create a hash using the same algorithm. If the hash values match, you know that the file you have matches the original file. Symmetric encryption is typically used for fast data encryption. Asymmetric encryption is used for encrypting small amounts of data or exchanging keys used with symmetric encryption. A private key is one of the keys used in asymmetric encryption.

File Integrity

Hashes are often used to prove the integrity of downloaded files. When a file is uploaded to a site, a hash can be generated. When the recipient downloads the file, they can create a hash of that file. If the recipient's hash matches the hash of the original file, you know that: > The downloaded file is complete (no missing parts). > The downloaded file was not corrupted during transfer. > The downloaded file is the same as the original and has not been altered by inserting malicious code or replaced with a virus or malware file. For this reason, files available for download are typically not encrypted as the hash proves their data integrity.

Secure logon credential exchange

Hashes can be used to secure logon credentials during an exchange. The password is used as the key to perform a hash on a text value, and only the hashed value is passed (not the password). The receiving host uses the same method to compare the hashes to verify the identity of the user. Examples of protocols that use this method are: > Challenge-Handshake Authentication Protocol (CHAP) > New Technology LAN Manager (NTLM) > Kerberos Passwords can be further secured by salting the hash. This is the process of adding random characters at the beginning or end of the password to generate a completely different hash. If a hacker intercepts the hash, they also must know which portion is the salt before beginning to crack the hash.

A birthday attack focuses on which of the following?

Hashing algorithms A birthday attack focuses on hashing algorithms. Birthday attacks exploit the probability that two messages using the same hash algorithm produce the same message digest. This is also known as exploiting collision. If two different messages or files produce the same hashing digest, a collision has occurred.

Hash Collisions

Hashing is a good file verification method, but it is not perfect. Depending on the algorithm used, there is a potential for hash collisions. A hash collision occurs when two completely different files generate the same hash. Rainbow table attacks take advantage of hash collisions. > A rainbow table is a table of passwords and their generated hashes. A hacker can use this table to try to match hashes instead of the actual password. > Hash collisions can be reduced using an algorithm that generates a longer hash and by salting the hash. Salt is random data that is used as an additional input to the function that hashes data.

How Hashing Works

Hashing is the process of generating a fixed-length hexadecimal string value from any file type or data. Hashes can be generated from messages, image files, data files, and most other types of data. This output is known as the message digest or hash.The output size varies depending on the algorithm being used. A proper hash function should have the following characteristics:

Hashing

Hashing is the process of using an algorithm, like MD5 or SHA, on data and generating a fixed-length key called a hash. The three main hashing algorithms used today are: > SHA-1, which generates a 128-bit key > MD5, which generates a 160-bit key > SHA-2 (SHA-256), which generates a 256-bit keyc

To obtain a digital certificate and participate in a public key infrastructure (PKI), what must be submitted and where?

Identifying data and a certification request to the registration authority (RA) The registration authority (RA) processes all requests for digital certificates. Registration and authentication requirements vary based on the class of certificate requested. Once the RA has successfully authenticated the requesting party, the request is forwarded to the certificate authority (CA) for certificate generation.

You want to protect data on hard drives for users with laptops. You want the drive to be encrypted, and you want to prevent the laptops from booting unless a special USB drive is inserted. In addition, the system should not boot if a change is detected in any of the boot files. What should you do?

Implement BitLocker without a TPM. If you use BitLocker without a TPM, system integrity checks are not performed. The TPM is required for saving the startup file information that is used to verify system integrity. When using BitLocker without a TPM, you must use a startup key on a USB device. When using a TPM, this is an optional configuration. Use BitLocker to encrypt the entire system volume and protect both operating system and user data. Use BitLocker with a Trusted Platform Module (TPM) to protect the boot environment components such as the BIOS, Master Boot Record, Boot Sector, Boot Manager, and Windows Loader. The system is shut down if a boot environment change is detected. Using BitLocker, drives are locked if they are moved to another computer, and you can require a startup key on a USB drive or a PIN before the system boots. EFS encrypts individual files. With EFS, only the user who encrypted the file and any additionally designated users can access the file. EFS does not provide integrity checks for boot files.

Limits of Cryptography

Implementing cryptography does come with some limitations. The following table covers some of these limitations.

Application-level encryption

In application-level encryption, the program that is used to create or modify the data is responsible for encrypting the data. > Data is encrypted before it goes into the database. > The resources required to set up this method can be prohibitive.

Key archival

In key archival, the key is backed up by the CA. To do this, the user sends the private key in a secure transmission to the CA to back it up. This method is often used in an organization that manages its own CA. If keys are lost, they will be readily available and easily accessed. However, if the CA is breached, all private keys will be compromised.

Mesh model

In the mesh model, multiple CAs are setup to issue certificates to each other. No CAs are configured in a subordinate relationship. > If a CA is compromised, certificates can still be trusted because multiple CAs have authenticated them. > This model is difficult and expensive to expand on a large scale.

You have downloaded a file from the internet. You generate a hash and check it against the original file's hash to ensure the file has not been changed. Which information security goal is this an example of?

Integrity Creating a hash of a file can be used to validate that the file has not been altered. This validates the integrity of the file. Applying a digital signature proves that the file is authentic and comes from the correct person. Applying a digital signature provides non-repudiation. This means that the sender cannot later deny having sent the file. Confidentiality is achieved through the encrypting of data or obfuscation of data.

Which of the following is the weakest hashing algorithm?

MD5 MD5 is the weakest hashing algorithm. It produces a message digest of 128 bits. The larger the message digest, the more secure the hash. SHA-1 is more secure because it produces a 160-bit message digest. Both DES and AES are symmetric encryption algorithms. DES is weaker than AES.

Message-Digest Algorithm 5 (MD5)

MD5 was developed by Ron Rivest in 1991. > MD5 generates a 128-bit message digest. > Many security vulnerabilities have been discovered with MD5. As such, it is no longer viable for security purposes. > MD5 is extremely susceptible to hash collisions. > MD5 is mainly used for file integrity.

Cryptographic systems provide which of the following security services? (Select two.)

Non-repudiation Confidentiality Cryptography is the science of converting data into a secret code to hide a message's meaning during transmission. Cryptographic systems provide the following security services: > Confidentiality by ensuring that only authorized parties can access data. > Integrity by verifying that data has not been altered in transit. > Authentication by proving the identity of the sender or receiver. > Non-repudiation by validating that communications have come from a particular sender at a particular time. Encryption is the process of using an algorithm to transform data from plaintext to ciphertext in order to protect the confidentiality, integrity, and authenticity of the message. Decryption is the procedure used to convert data from ciphertext into plaintext. Cryptanalysis is the method of recovering original data that has been encrypted without having access to the key used in the encryption process.

Your computer system is a participant in an asymmetric cryptography system. You've crafted a message to be sent to another user. Before transmission, you hash the message and then encrypt the hash using your private key. You then attach this encrypted hash to your message as a digital signature before sending it to the other user. Which protection does the private key-signing activity of this process provide?

Non-repudiation Signing a digital signature with the private key provides non-repudiation. A digital signature activity as a whole does not provide protection for confidentiality because the original message is sent in clear form. Hashing of any sort at any time, including within a digital signature, provides protection for integrity. No form of cryptography provides protection for availability.

When a sender encrypts a message using their own private key, which security service is being provided to the recipient?

Non-repudiation When a sender encrypts a message using their own private key, the security service of non-repudiation is being provided to the recipient. The encrypted message can be freely decrypted using the public key. Because only the sender knows the private key, encrypting the message with the private key proves that only the sender could have sent the message. Integrity is provided when hashing is used. Because the public key is freely available, the encryption does not provide confidentiality (anyone with the public key could read the message contents). Availability is not provided by any form of cryptography.

Which technology was developed to help improve the efficiency and reliability of checking the validity status of certificates in large, complex environments?

Online Certificate Status Protocol Online Certificate Status Protocol (OCSP) is the technology developed to improve the efficiency and reliability of checking the validity status of certificates in large, complex environments. OCSP allows clients to query a CA or registration authority (RA) and quickly learn whether a certificate is valid or has been revoked. OCSP is a significant improvement over the CRL mechanism. CRLs were static lists that were distributed periodically to CAs and RAs. However, CRLs were often out of date. Key escrow and private key recovery are not related to certificate status checking.

Privacy-Enhanced Email (PEM)

PEM certificates are the most common certificates in use. PEM was originally created to securely encode emails, but S/MIME and PGP quickly replaced it. The format PEM uses is perfect for encoding certificates. > PEM certificates are base64 DER formatted. This means the binary information is encoded into ASCII text. > The ASCII text is sandwiched between a header and footer that identify the data type. Common identifiers are: - CERTIFICATE - CERTIFICATE REQUEST - PRIVATE KEY - X509 CRL > A single PEM certificate can contain the intermediate certificate, root certificate, and private key. > PEM certificates can have a .pem, .crt, .cer, or .key file extension.

Pretty Good Privacy

PGP is a commercial encryption program that is now owned by NortonLifeLock (previously Symantec). PGP is used by products that protect laptops, desktops, USB drives, optical media, and smart phones.

Public Key Cryptography Standards (PKCS)

PKCS is a group of standards published by RSA Security. These standards were published to promote the use of the cryptography techniques, such as the RSA algorithm, and several others.

7.5.4 Certificate Types Facts

PKI certificates are used to verify an organization's identity and ownership of a public key. When an organization requests a certificate, they must choose which type they need. The Certificate Authority needs to validate the organization before issuing the certificate. The level of validation depends on the certificate type being requested. This lesson covers the following topics: > Certificate types > SSL validation levels

An attacker is attempting to crack a system's password by matching the password hash to a hash in a large table of hashes he or she has. Which type of attack is the attacker using?

Rainbow A rainbow attack uses rainbow tables. A rainbow table is a table of passwords and their generated hashes. A hacker can use this table to try to match hashes instead of the actual password. Cracking is the process of finding a password. A brute force attack does not use a table of hashes. RIPEMD is a family of cryptographic hash functions that was first developed in 1992 as part of the EU's RIPE project.

In the certificate authority trust model known as a hierarchy, where does trust start?

Root CA Trust starts at the Root CA in all trust models. An Issuing CA can be a Root CA or a CA at any level below the root. A third-party CA may be the source of trust, but even then, the trust starts at a Root CA located somewhere. A registration authority (RA) is a limited-functionality CA where certificates are verified, but no new certificates can be issued.

Subject Alternative Name (SAN)

SAN certificates allow an organization to cover multiple domains with one certificate. For example, TestOut could cover the following domains in a single SAN certificate: > TestOut.com > TestOut.net > LabSim.com

Secure Hash Algorithm (SHA)

SHA is a family of hashes. > SHA is a government standard. > First published in 1991 by the National Institute of Standards and Technology (NIST). > SHA-2 was published in 2001 and has become one of the standard hash functions in use today. > Used in many security protocols such as TLS, SSL, PGP, SSH, and IPSec. > Generates message digests that are 224, 256, 384, or 512 bits in size. SHA-3 was published in 2015, but is not meant to replace SHA-2. SHA-2 has yet to be cracked. NIST wanted an alternative available for people to use. Message digests generated by SHA-3 are fully compatible with SHA-2.

Which of the following does not or cannot produce a hash value of 128 bits?

SHA-1 SHA-1 produces hash values of 160 bits. MD5 and MD2 both produce hash values of 128 bits. RIPEMD is a family of cryptographic hash functions that was first developed in 1992 as part of the EU's RIPE project.

What is the process of adding random characters at the beginning or end of a password to generate a completely different hash called?

Salting Salting is the process of adding random characters at the beginning or end of the password to generate a completely different hash. If a hacker intercepts the hash, he or she would need to also know which portion is the salt before beginning to crack the hash. Deterministic is a characteristic of a hash function that means the same data always generates the same hash. A collision is when two different pieces of data generate the same hash. The avalanche effect states that changing any bit of data results in a completely different hash.

Self-Signed Certificate

Self-signed certificates are certificates that have not been validated or signed by a CA. > Self-signed certificates are easy and free to make. > Self-signed certificates do not provide the same protection and security as a CA-validated certificate. > When a user visits a website using a self-signed certificate, they see a warning that the certificate is not trusted.

Which form of cryptography is best suited for bulk encryption because it is so fast?

Symmetric key cryptography Symmetric cryptography is best suited for bulk encryption because it is much faster than asymmetric cryptography. Hashing is not used for encryption; it is only used to verify the integrity of data. Public key cryptography, also known as asymmetric cryptography, is best suited for small amounts of data. Often, asymmetric cryptography is used to exchange symmetric cryptography keys, and then the symmetric cryptography keys are used to encrypt communication traffic.

Transparent Data Encryption (TDE)

TDE encrypts the entire database and all backups. > Encrypts data at rest, which is data not being currently used. > This method is called transparent because when an authorized user needs to access the data, it is automatically decrypted so the user does not see the process or need to do anything extra.

Trusted Platform Module

TPM is a hardware chip on the motherboard that can generate and store cryptographic keys.

An SSL client has determined that the certificate authority (CA) issuing a server's certificate is on its list of trusted CAs. What is the next step in verifying the server's identity?

The CA's public key must validate the CA's digital signature on the server certificate. Once an SSL client has identified a CA as trusted, it uses the CA's public key to validate the CA's digital signature on the server certificate. If the digital signature can be verified, the client accepts the server certificate as a valid certificate issued by a trusted CA. SSL clients verify a server's identity using the following steps: 1. The client checks the server's certificate validity period. The authentication process stops if the current date and time fall outside of the validity period. 2. The client verifies that the issuing certificate authority is on its list of trusted CAs. 3. The client uses the CA's public key to validate the CA's digital signature on the server certificate. If the digital signature can be verified, the client accepts the server certificate as a valid certificate issued by a trusted CA. 4. To protect against man-in-the-middle attacks, the client compares the actual DNS name of the server to the DNS name on the certificate.

Data Recovery Agent

The DRA is an account that has been granted the right to decrypt files and folders on a EFS.

Encrypting File System (EFS)

The Encrypting File System (EFS) was introduced with NTFS version 3 and has been included in every version of Windows since Windows 2000 except for in the Home editions. EFS provides an easy and seamless way for users to encrypt files on their Windows computers. EFS is only used to encrypt individual files and folders. EFS combines the speed of symmetric encryption with the convenience of asymmetric encryption, using a process called key encapsulation. The process for a user to encrypt a file is as follows: 1. The user accesses Properties and from the General tab clicks Advanced. From there, the user selects Encrypt contents to secure data. 2. Windows generates a pseudo-random number called the File Encryption Key (FEK). Windows uses the FEK with the AES encryption algorithm to encrypt the file. 3. The FEK is then encrypted using the user's public key. The encrypted FEK is stored in the file's header in a special location called the Data Decryption Field (DDF). 4. The decryption process is the opposite. The user's private key is used to first unlock the DDF and get the FEK. The FEK is then used to decrypt the file The encryption and decryption process relies on the user's password being kept safe. If the user account becomes corrupted or the password is forgotten, any encrypted files are lost. To help remedy this, a data recovery agent (DRA) can be set up. The DRA is simply another account that can decrypt the encrypted files. > The DRA used to be automatically configured as the system administrator in older versions of Windows. Nowadays, it is no longer automatically set up. > A local DRA for an individual workstation can be configured through the machine's Group Policy settings. > A domain-wide DRA can be configured in Active Directory. Only a domain administrator can set up a domain-wide DRA. Additional security considerations are: > Decryption keys can be backed up to an external USB drive. This ensures access even if the Windows system completely crashes. > A file is automatically unencrypted when it is moved or copied to a non-NTFS formatted device or media. A file is also automatically unencrypted when you copy a file over the network using the SMB Protocol. > Key security relies on the user having a strong password and following proper password security protocols.

Online Certificate Status Protocol (OCSP)

The Online Certificate Status Protocol (OCSP) is a protocol that web browsers can use to quickly check the status of a certificate. The purpose of OCSP is to replace the need for the CRL. OCSP is commonly implemented using: > OCSP Stapling - OCSP stapling can be used to help with performance. Stapling means that the server holding the certificate also provides revocation information. This server sends a query to the OCSP responder at set intervals to verify the status of it's certificate. The server will attach, or staple, the response to it's certificate. - During the initial SSL or TLS handshake between the server and a user's web browser, the OCSP validation is sent along with the certificate removing the need for the browser to send a separate request for the certificate status. > Certificate pinning - Certificate pinning is when an application, such as a web browser, has a server's certificate hard coded into it. When the application connects to the server, it downloads and checks the certificate. If the two certificates don't match, the application takes appropriate action including blocking the connection. - Certificate pinning was never truly adopted by web browsers and is mostly used in organizations that have their own CA setup.

Public Key Cryptography Standards #12 (PKCS #12)

The PKCS #12 standard is also used to format certificates. It has the following characteristics: > Is also known as the Personal Information Exchange Syntax Standard. > Is based on the PEM standard. > Holds certificate chains and the private key. > Protects certificates and private keys with a password. > Uses a file extension of .pfx or .p12.

Public Key Cryptography Standards #7 (PKCS #7)

The PKCS #7 standard is used to format certificates and has the following characteristics: > Is also known as the Cryptographic Message Syntax (CMS) standard. > Is based on the PEM standard. > Can contain only the intermediate certificate and root certificate, but not the private key. > Is mainly used with digital signatures. > Uses a file extension of .p7b or .p7c.

Certificate Formats

The X.509 standard defines the format for SSL certificates. The following table shows the more common formats:

You have transferred an encrypted file across a network using the Server Message Block (SMB) Protocol. What happens to the file's encryption?

The file is unencrypted when moved. A file is automatically unencrypted when you copy it over a network using the SMB Protocol. The encryption does not carry over to the new location, nor does the file inherit from the new location. A file can be moved using the SMB Protocol.

RACE Integrity Primitives Evaluation Message Digest (RIPEMD)

The first version was based on the MD4 function. In 1996, in response to security issues discovered in the first version, Belgian researchers developed four updated algorithms. > RIPEMD-128 > RIPEMD-160 > RIPEMD-256 > RIPEMD-320 RIPEMD is not as popular as SHA-2, but is used frequently with Bitcoin and other cryptocurrencies.

One-way

The hash cannot be reverse engineered.

Organization

The legal name of the organization. The name cannot be abbreviated and any suffixes, such as LLC, must be included. Example: TestOut Corporation

SSL Validation Levels

The most common use of certificates is for websites using SSL or TLS. These certificates prove to the user that the site is legitimate and trustworthy. When a user visits a website that has been issued a certificate, they see a lock icon in the address bar. The user can click that lock to view the certificate information. When a website purchases a certificate, there are three different levels of validation a CA can offer. The following table shows each level and how they are validated and used:

Extended Validation (EV)

The most common use of certificates is for websites using Secure Socket Layer (SSL) or Transport Layer Security (TLS). These certificates prove to the user that the site is legitimate and trustworthy. When visiting a website that has been issued a certificate, the user sees a lock icon in the address bar. The user can click the lock to view the certificate information. The highest level of these certificates is the Extended Validation certificate. The CA conducts a thorough and standardized identity verification process before issuing an Extended Validation certificate. This process includes the applicant proving: > Exclusive rights to the domain. > The organization's legal, physical, and operational existence. > The organization's authorization for the issuance of the certificate. Extended validation certificates can take up to 5 days to be issued.

Encryption with Steganography

There has been an increased amount of research done on how to best combine encryption with steganography. The process essentially follows the steps below: 1. Encrypt plaintext with a private key to generate ciphertext. 2. The ciphertext is hidden inside of a media file, such as an image, using steganography. 3. The recipient extracts the ciphertext and decrypts it using the matching public key. 4. Because the ciphertext is hidden in the image file, someone intercepting the message would have to know its there before being able to decrypt it.

Organizational unit

This is the division that is handling the certificate. Example: IT Department

7.1.9 Blockchain Facts

This lesson covers the following topics: > Blockchain > Blockchain implementations

7.5.8 Extended Validation Facts

This lesson covers the following topics: > Extended validation > Certificate formats > Public key cryptography standards

7.3.3 Hashing Facts

This lesson covers the following topics: > How hashing works > Hashing uses > Hash collisions > Hashing algorithms

Private Key Safety

To ensure data can always be recovered, you should create a backup of the private keys. It is important to have a backup and equally important that the backup is kept safe. The following table shows two main methods to backup private keys:

Database Encryption

Today, many organizations store sensitive data such as customer billing information in databases. Keeping this data encrypted helps protect it if a hacker ever gains access to the database. Databases consist of multiple tables that use columns and rows to store data. The following table describes the three main methods of data encryption:

Which of the following database encryption methods encrypts the entire database and all backups?

Transparent Data Encryption (TDE) Transparent Data Encryption (TDE) encrypts the entire database and all backups. TDE: > encrypts data at rest, which is data not being currently used. > is called transparent because when an authorized user needs to access the data, it is automatically decrypted so the user does not see the process or need to do anything extra. Column-level encryption allows the administrator to encrypt each column separately. In application-level encryption, the program that is used to create or modify the data is responsible for encrypting the data. BitLocker is a Microsoft security solution that encrypts the entire contents of a hard drive, protecting all files on the disk.

Trust Models

Trust models are configurations you can use to setup certificate authorities. The trust model you choose depends on the number of certificate authorities being implemented and their use. The following table explains each of these models:

Trusted Platform Module (TPM)

Trusted Platform Module (TPM) is a hardware chip on the motherboard that can generate and store cryptographic keys. TPM version 2.0 was released in 2014. Beginning with Windows 10 version 1607, Microsoft required that TPM 2.0 be enabled by default on all new computers. > A TPM is required to check the integrity of startup files and components in BitLocker implementations. - The TPM generates a hash of the startup files to verify the integrity of those files. - Additionally, the TPM creates a hash of system components. This hash acts as a validation check of the system to ensure that system components have not changed. The hash can also be used to uniquely identify the system. > Windows Credential Guard requires the computer to have a TPM chip installed. - A TPM provides protection for virtual-based security encryption keys that are stored in the firmware. This helps protect against attacks involving a physically present user with BIOS access. > A TPM can generate truly random numbers, thus preventing entropy. > TPM provides full support for asymmetric encryption; therefore, it can generate public and private keys. > A TPM also provides encrypted storage for user passwords, encryption keys, and digital certificates. > Windows 10 can pull stored keys directly from the TPM without loading them into the RAM where they would be more vulnerable to an attack.

Twofish

Twofish was one of the five finalists for the AES contest but ultimately was not chosen. > Twofish uses keys up to 256 bits in size. > Twofish is slower than AES.

User and Computer Certificate

User and computer certificates are used in a network environment to identify and validate specific users or computers. When a user or computers logs into a network, their certificate is sent to the server for validation. This provides extra security to the network.

7.5.10 Certificate Concepts Facts

Using digital certificates to share public keys and validate organizations is a critical component of doing business over the internet. Certificate authorities (CAs) are the trusted organizations that validate and administer digital certificates. This lesson covers the following topics: > Certificate chaining > Certificate revocation list (CRL) management > Trust models > Private key safety

Which of the following items are contained in a digital certificate? (Select two.)

Validity period Public key Digital certificates create a link between identities and public keys. A certificate contains the information necessary to identify the public key owner. Certificates include fields detailing the Issuing CA and the standards version used to generate the certificate, as well as a certificate serial number, all approved uses for the certificate, the certificate owner, the public key and algorithm, the validity period, and the algorithms used to digitally sign the certificate. Additional functionality and data may be added through the use of certificate extensions.

Partitions/volumes

When setting up BitLocker, the hard disk must be configured with two partitions - the System and Boot. > The system partition (system volume) contains the boot loader. This is a piece of software responsible for booting the operating system. This partition holds the boot sector and is marked active. > The boot partition (boot volume) is the partition that contains the operating system folder and all personal files and programs. With BitLocker, only the boot partition is encrypted.

Encryption options

When setting up BitLocker, you can choose how much of the drive should be encrypted. Options include: > Encrypt used disk space only - Introduced with Windows 10, this option only encrypts the portion of the drive that is currently in use. As data is written to the drive, it is encrypted. This method speeds up the encryption process and is recommended for new drives. > Encrypt entire drive - This is recommended for drives that are already in use. However, this process can take a very long time depending on the size of the drive. This process encrypts all data, even data that may have been deleted but still remains hidden on the drive.

Wildcard Certificate

Wildcard certificates are similar to SAN certificates. But instead of covering multiple domains, the organization can cover one domain and multiple subdomains. For example, TestOut could cover the following in one certificate: > quiz.testout.com > labs.testout.com > videos.testout.com

Which standard is most widely used for certificates?

X.509 The standard for certificates that is most widely used is X.509. This standard defines the key elements that must exist within a certificate. This standard is used by public key infrastructure (PKI), SSL, IPsec, DES, and many other infrastructure components and technologies. HTTP 1.1 is the latest version of the protocol used to transmit web resources from a web server to a web client. SSL v.3.0 uses certificates, but this is the standard for the secure session protocol for protecting web communications. 802.1x is a networking protocol that defines how to support Extensible Authentication Protocol (EAP) over a wired or wireless LAN.

7.3.5 Compare an MD5 Hash Lab

You are the IT administrator at a small corporate office. You just downloaded a new release for a program you use. You need to make sure the file was not altered before you received it. Another file containing the original file hash was also downloaded. Both files are located in the C:\Downloads folder. In this lab, your task is to use MD5 hash files to confirm that the Release.zip file was unaltered. From Windows PowerShell: > Generate a file hash for the new Release.zip file. > View the hash of the original file stored in the release821hash.txt file. > Use the following command to compare the original hash of the Release.zip file to its calculated hash to see if they match: "new hash" -eq "known hash" You can highlight text in PowerShell and right-click it to copy the text to the active line. If using Chromebooks, highlight the desired hash amount and then click on the touchpad using 2 fingers to copy and paste the value. > Answer the question. > The new hash is the hash generated by the get-filehash file_name -a md5 command. > The known hash is the hash generated by the get-content file_name.txt command. > Include the quotation marks and the file extensions with the file names in the commands. Q1Do the file hashes match? Correct answer: No Complete this lab as follows: 1. View the files in the C:\Downloads folder. a. Right-click Start and select Windows PowerShell (Admin). b. At the prompt, type cd C:\downloads and press Enter to navigate to the directory that contains the files. c. Type dir and press Enter to view the available files. 2. Confirm that the Release.zip file is unaltered. a. Type get-filehash Release.zip -a md5 and press Enter to view the MD5 hash. b. Type get-content release821hash.txt and press Enter to view the known hash contained in the .txt file. c. Type "new hash" -eq "known hash" and press Enter to determine whether the file hashes match. * The new hash is the hash generated by the get-filehash file_name -a md5 command. *The known hash is the hash generated by the get-content file_name.txt command. *Include the quotation marks and the file extensions with the file names in the commands. 3. Answer the question. a. In the top right, select Answer Questions. b. Answer the question. c. Select Score Lab.

7.5.6 Manage Certificates Lab

You are the IT administrator for a growing corporate network. You manage the certification authority for your network. As part of your daily routine, you perform several certificate management tasks. CorpCA, the certification authority, is a guest server on CorpServer2. In this lab, your task is to complete the following: > Your network uses smart cards to control access to sensitive computers. Currently, the approval process dictates that you manually approve smart card certificate requests. Approve pending certificate requests for smart card certificates from tsutton and mmallory. > Deny the pending web server certificate request for CorpSrv12. > User bchan lost his smartcard. Revoke the certificate assigned to bchan.CorpNet.com using the Key Compromise reason code. > Unrevoke the CorpDev3 certificate. Complete this lab as follows: 1. Access Certification Authority on the CORPSERVER2 server. a. From Hyper-V Manager, select CORPSERVER2. b. Maximize the window for easier viewing. c. From the Virtual Machines pane, double-click CorpCA. d. From Server Manager's menu bar, select Tools > Certification Authority. e. Maximize the window for easier viewing. f. From the left pane, expand CorpCA-CA. 2. Approve the pending certificate request for tsutton and mmallory. a. Select Pending Requests. b. From the right pane, scroll to the Request Common Name column. c. Right-click tsutton and select All Tasks > Issue to approve the certificate. d. Right-click mmallory and select All Tasks > Issue. 3. Deny the pending request for CorpSrv12. a. Right-click CorpSrv12.CorpNet.com and select All Tasks > Deny. b. Select Yes. 5. Revoke bchan's certificates. a. From the left pane, select Issued Certificates. b. From the right pane, right-click bchan.CorpNet.com and select All Tasks > Revoke Certificate. c. Using the Reason code drop-down menu list, select Key Compromise. d. Select Yes. 5. Unrevoke the CorpDev3 certificate. a. From the left pane, select Revoked Certificates. b. From the right pane, right-click CorpDev3.CorpNet.com and select All Tasks > Unrevoke Certificate.

7.4.8 Configure BitLocker with a TPM Lab

You work as the IT security administrator for a small corporate network. The employee in Office 1 is working on a very sensitive project. Management is concerned that if the hard drive in the computer were stolen, sensitive information could be compromised. As a result, you have been asked to encrypt the entire System volume. The Office1 computer has a built-in TPM on the motherboard. In this lab, your task is to configure BitLocker drive encryption as follows: > From within the computer's BIOS, turn on and activate TPM Security. > From Windows, turn on BitLocker for the System (C:) drive. > Back up the recovery key to the \\CorpServer\BU-Office1 folder. > Encrypt the entire System (C:) drive. > Use the new encryption mode. > Run the BitLocker system check. Complete this lab as follows: 1. (Optional) Try to enable BitLocker. a. From the search field on the Windows taskbar, type Control. b. From Best match, select Control Panel. c. Select System and Security. d. From the right pane, select BitLocker Drive Encryption. e. Under Operating system drive, select Turn on BitLocker.An error message at the bottom of the screen indicates that a TPM security device was not found. f. Select Cancel. 2. Access the BIOS settings. a. Right-click the Start menu and then select Shut down or sign out > Restart to reboot your computer. b. When the TestOut logo appears, press Delete to enter the BIOS. 3. Turn on and activate the TPM. a. From the left pane, expand and select Security > TPM Security. b. From the right pane, select TPM Security and then select Apply. c. Select Activate and then select Apply. d. Select Exit. *Your computer will automatically reboot. 4. Turn BitLocker on. a. From the search field on the Windows taskbar, type Control. b. From Best match, select Control Panel. c. Select System and Security. d. Select BitLocker Drive Encryption. e. Under Operating system drive, select Turn on BitLocker. Windows begins the Drive Encryption setup. 5. Back up a BitLocker recovery key. a. Select Save to a file. b. In the left pane, expand and select Network > CorpServer > BU-Office1. c. Select Save. d. Select Next. 6. Configure BitLocker encryption. a. Select Encrypt entire drive and then select Next. b. Make sure that New encryption mode is selected and then select Next. c. Select Run BitLocker system check and then select Continue. d. Select Restart now. The computer will reboot, and the encryption process will run automatically. e. When the encryption process is complete, select Close. 7. Verify that encryption is enabled. a. From the Windows taskbar, select File Explorer. b. From the left pane, select This PC. c. From the right pane, verify that the System (C:) drive shows the encryption lock icon.

You have just downloaded a file. You create a hash of the file and compare it to the hash posted on the website. The two hashes match. What do you know about the file?

Your copy is the same as the copy posted on the website. A hash is a function that takes a variable-length string (message) and compresses and transforms it into a fixed-length value. Hashes ensure the data integrity of files and messages in transit. The sender and the receiver use the same hashing algorithm on the original data. If the hashes match, it is assumed that the data is unmodified. Hashes do not ensure confidentiality (in other words, hashes are not used to encrypt data). Non-repudiation proves the source of a file and is accomplished using digital signatures.

7.1.11 Hide Files with OpenStego Lab

You are the IT security administrator for a small corporate network. Recently, some of your firm's proprietary data leaked online. You have been asked to use steganography to encrypt data into a file that is to be shared with a business partner. The data will allow you to track the source if the information is leaked again. In this lab, your task is to use OpenStego to hide data in photos as follows: > Encrypt the user data into the file to be shared. > Name the file send.png and save it in the Documents folder. > Password-protect the file with NoMor3L3@ks! as the password. > Confirm the functionality of the steganography by extracting the data and opening the file to confirm that the associated username has been embedded into the file. Complete this lab as follows: 1. Encrypt the user data into the file to be shared. a. In the search field on the taskbar, type OpenStego. b. Under Best match, select OpenStego. 2. Select the Message, Cover, and Output Stego files. a. For Message File, select the ellipses [...] button at the end of the field. b. Double-click John.txt to select the file. c. For Cover File, select the ellipses [...] button at the end of the field. d. Double-click gear.png to select the file. e. For Output Stego File, select the ellipses [...] button at the end of the field. f. In the File name field, enter send.png and then select Open. 3. Password protect the file. a. In the Password field, enter NoMor3L3@ks! b. In the Confirm Password field, enter NoMor3L3@ks! c. Select Hide Data. d. Select OK. 4.Extract the data and open the file. a. Under Data Hiding, select Extract Data. b. For the Input Stego File field, select the ellipses [...] button. c. Double-click send.png to select the file with the encryption. d. For the Output Folder for Message File, select the ellipses [...] button. e. Double-click Export to set it as the destination of the file output. f. Click Select Folder. g. In the Password field, enter NoMor3L3@ks! as the password. h. Select Extract Data. i. Select OK. 5. Verify that the decryption process was successful. a. From the taskbar, select File Explorer. b. Double-click Documents to navigate to the folder. c. Double-click Export to navigate to the folder. d. Double-click John.txt.

Each block goes through the same process:

1. User1 requests a transaction with User2. The request is made using User1's personal secret key and User2's public key. 2. The transaction is represented online as a block. 3. The block is distributed to everyone on a peer-to-peer network. 4. The network users verify the transaction is valid. 5. The block is added to the chain. This provides a indisputable and transparent record of the transaction. 6. The contents of the transaction move to User2. The entire transaction happens very quickly, usually within a matter of minutes. Every node contains a copy of the ledger. If a hacker changed a transaction, it wouldn't matter because a copy of the transaction is stored on many other computers. Each node plays an important part in the blockchain. Each node must prove itself by performing work before being allowed to join the network. This is typically done through mining. Mining is the process of adding blocks to the chain. Each block has a 64-digit hexadecimal hash generated by extremely complex math computations. Generating the hash requires a lot of time and computing power. The process is split between each node. As a reward for performing these computations, the nodes are usually paid with cryptocurrency, like Bitcoin. Even though each transaction is publicly visible, all personal information is encrypted and hidden from everyone, even the nodes. Because it's a shared ledger and every transaction is publicly available, all persons involved can be held accountable for their actions.

Supply Chains

A blockchain could be used to track the movement of product such as food. The ability to follow and see every stop the product has made on its way to the consumer would provide assurances of the product's safety.

Collision attack

A collision attack tries to find two inputs that produce the same hash value. This type of attack is often used on digital signatures. > If a hacker wanted to get User2 to sign a document by making it seem like it came from User1, the hacker would generate two documents that generate the same hash. > The hacker would send one document to User1 and get that signature. > The signature would be attached to the second document and sent to User2. Because the hashes are identical, User2 thinks the document is legitimate and has been signed by User1. Generating longer hash outputs is the key to stopping these types of attacks.

Downgrade attack

A downgrade attack forces the system to use an older, less secure communication protocol. > SSL exploitation is a common implementation of this attack. A hacker can set up their computer to only use SSL so that when the request is sent to the server, the server downgrades from TLS to SSL to communicate. This then allows the hacker to launch SSL-based attacks on the server. > Downgrade attacks are often used as part of a man-in-the-middle (MITM) attack. The hacker can intercept a HTTPS packet and downgrade it to a HTTP packet. If the server is not configured properly, the server responds using HTTP. This allows the hacker to now see all communications. To prevent downgrade attacks, servers must be set up to not support these older and less secure protocols. Proper server configuration is the key to stopping these types of attacks.

Hardware security module (HSM)

A hardware security module (HSM) is a piece of hardware and associated software/firmware that is connected to a computer system to provide cryptographic functions.

Hybrid cryptosystem

A hybrid cryptosystem combines the efficiency of symmetric encryption with the convenience of asymmetric encryption.

Stream Cipher

A stream cipher is a symmetric encryption method that encrypts data one bit at a time. The stream cipher is based on the one-time pad (OTP) concept, which was used extensively during World War 2. Consider the following OTP characteristics: > The OTP uses a symmetric encryption key that is the same length as the data being encrypted. > The encryption key is used to encrypt the data using a process called XORing. This means that two binary strings are compared. If the bits match, a 0 is generated. If the bits don't match, a 1 is generated. The output of the XOR process is the ciphertext. > The OTP demonstrates what is called perfect secrecy. This means that it is just as, if not more, difficult for a hacker to brute-force the key as it would be to brute-force the data itself. > The OTP only provides perfect secrecy if the secret key is only used once. If used more than once, a hacker could begin to decode it. > OTP works well when dealing with small messages, but it becomes impractical when dealing with large data due to the keys being so extensive. A stream cipher solves the problem of having excessively large keys associated with OTP by using a smaller, fixed-length seed key such as one that is 2048 bits in length. The following describes the process of creating a seed key: 1. The seed key is run through a pseudorandom number generator which outputs a new and unique encryption key that is the same size as the data being encrypted. This new key is called a keystream. 2. The keystream is XORed with the data to create the ciphertext. 3. The seed key can be used repeatedly throughout the encryption process. The seed key is run through a pseudorandom number generator which outputs a new and unique encryption key that is the same size as the data being encrypted. This new key is called a keystream. The keystream is XORed with the data to create the ciphertext. The seed key can be used repeatedly throughout the encryption process.

Encryption key

A string of bits randomly generated using a specific cipher. An encryption key is used to encrypt or decrypt data.

Digital signatures

By combining a user's private encryption key and a hash of the data, a user can create a digital signature. A digital signature verifies that the data is legitimate and provides non-repudiation. This means that the sender cannot deny having sent the file.

7.2 Cryptography Implementations

As you study this section, answer the following questions: > How can cryptography support the goals of information security? > Why is reusing encryption keys considered a weakness? > What is a digital signature? What benefits does it provide? > What are the three main hashing algorithms in use today? > What functionality does a Trusted Platform Module (TPM) chip provide?

7.1 Cryptography

As you study this section, answer the following questions: > What is the difference between symmetric and asymmetric encryption? > Which algorithms can be used to generate a hash? > What does a digital signature provide? > What is a legitimate use for steganography? > What are uses of blockchain in addition to cryptocurrency? > What type of attack uses a large list of common words and phrases? In this section, you will learn to: > Crack a symmetric encryption key. > Use steganography to hide a file.

Asymmetric Encryption

Asymmetric encryption uses two keys instead of one. A user's public key is used to encrypt the data. That user then uses their private key to decrypt the data. The private key only decrypts data that was encrypted using its matching public key. Asymmetric encryption is used in most communication over the internet. The following is an example of how asymmetric encryption is used: 1. When a user wants to log into a website, the browser sends a request to the web server for the public key. 2. The user's login information is encrypted using the public key and sent to the server. 3. The server uses its private key to decrypt the user's login information. Asymmetric encryption is also used to create digital signatures. > By using a private key along with a hash of the data being sent, a digital signature is created. > The recipient can verify the digital signature to ensure the message is legitimate and actually comes from the sender. > Digital signatures are not meant to encrypt or secure data. Their main function is to provide non-repudiation, which means the sender cannot deny having sent the message. Digital signatures are also used to verify that the data transmitted was not changed or corrupted.

Blockchain

Blockchain is a unique and increasingly popular implementation of cryptography. A blockchain is a decentralized and distributed ledger that records and verifies transactions between two parties. Blockchain uses cryptography to keep data secure. It was developed in 2008. Each block is a transaction that is stored in a public database (the chain). A transaction can involve cryptocurrency, contracts, records, or other types of information. The first big use of the blockchain was the cryptocurrency, Bitcoin. The purpose of Bitcoin is to provide a method for people to make online transactions without the use of a centralized third party such as a bank. Each block contains information about the transaction including: > Time > Date > Parties involved > A unique hash that separates the block from other blocks on the chain

Which of the following algorithms are used in symmetric encryption? (Select two.)

Blowfish 3DES 3DES and Blowfish are symmetric encryption algorithms. RSA, Diffie-Hellman, and ECC are asymmetric encryption algorithms.

Blowfish

Blowfish was developed in 1993 by Bruce Schneier. It was meant to be a replacement for DES. > Blowfish is unpatented so that it can be used freely by anyone. > Blowfish uses a 128-bit key. > Vulnerabilities have been discovered in the Blowfish cipher and it is recommended to use its successor, Twofish, instead.

Cipher Block Chaining (CBC)

CBC is similar to ECB except this mode uses an initialization vector (IV). > The IV is a starting variable that is XORed with the plaintext of the current block to encrypt the data. > The IV for the starting block is a randomly generated value. Each subsequent IV is the ciphertext from the previous block. > CBC is more secure than ECB due to the IV, but it is slower because blocks cannot be encrypted simultaneously.

Cipher Feedback Mode(CFB)

CFB also uses an IV, but instead of using it on the plaintext, the IV is encrypted first. That output is then XORed with the plaintext to create the block of ciphertext. > This is the equivalent of using a one-time pad to encrypt the data. > The IV for the starting block is a randomly generated value. Each subsequent IV is the ciphertext from the previous block.

Cryptography Overview

Cryptography is defined as the process of writing or solving messages using a secret code. A form of cryptography called encryption has been used throughout the ages, mainly to keep messages out of the hands of enemies. Encryption is the process of converting normal readable text into something that is unintelligible called ciphertext. A cipher is the method, or algorithm, used to encrypt or convert the data. One of the more popular forms of encryption is the Caesar cipher. This encryption method works by shifting each letter in the alphabet a certain number of spaces to the right or left. In the example below, the cipher is shifting to the right by three letters. A becomes D, B becomes E, C becomes F, and so forth.. To decrypt the message, the reader must know how many spaces to shift the letters. For example, to encrypt the word TESTOUT using the Caesar Cipher with a shift of 3 to the right, TESTOUT would become WHVWRXW. Below is the complete Caesar cipher using a shift of three letters to the right (you can see below which letters are used when they are shifted 3 spaces): Original Alphabet - A-Z Shifted by 3 letters - D E F G H I J K L M N O P Q. . . This is a very simple example of cryptography and is easily decrypted. With today's computing power, encryption methods used are much more complicated and powerful.

Which of the following encryption mechanisms offers the least security because of weak keys?

DES DES offers the least encryption security of all the cryptography systems in this list. DES has a limitation of 56-bit keys, the weakest of those listed here. The strength of a cryptosystem lies not only in long keys but in the algorithm, initialization vector or method, the proper use of the keyspace, and the protection and management of keys. AES (128-, 192-, and 256-bit keys), TwoFish (up to 256-bit keys), and IDEA (128-bit keys) all support stronger keys than DES.

Digital Signature Algorithm (DSA)

DSA was proposed in 1991 by NIST and became the government standard in 1993 > DSA is only used for creating digital signatures. > It uses a different algorithm than RSA but provides the same level of security.

Which type of password attack employs a list of pre-defined passwords that it tries against a login prompt?

Dictionary attack A dictionary attack is a type of brute-force attack. A hacker uses a list of words and phrases to try to guess the decryption key. > Dictionary attacks work well if weak passwords are used. > Using longer and uncommon passphrases is the best way to secure data against these attacks. A collision attack tries to find two inputs that produce the same hash value. This type of attack is often used on digital signatures. A birthday attack combines a collision attack and brute-force attack. The name is taken from the birthday probability math problem. A downgrade attack forces the system to use an older, less secure communication protocol.

Electronic Code Book (ECB)

ECB is the simplest mode of operation. > Each block of plaintext data is encrypted separately. > Blocks of data can be encrypted simultaneously allowing for faster encryption. > The biggest disadvantage is that blocks with identical data will generate the same ciphertext.

Elliptic Curve Cryptography (ECC)

Elliptic Curve Cryptography is one of the newer methods being implemented. ECC is able to generate smaller keys that are more secure than most other methods. Many websites today use ECC to secure connections and data transmissions.

Elliptic Curve Cryptography (ECC)

Elliptic Curve Cryptology is one of the newer methods being implemented. It was originally introduced in 1985. It did not enter wide usage until 2004. > ECC is able to generate smaller keys that are more secure than most other methods. > Many websites today use ECC to secure connections and data transmissions.

Confidentiality

Encrypting data or obfuscating data provides data confidentiality. Obfuscation is different than encryption, but is a form of cryptography. > Encryption is the process of transforming readable data into something unreadable. This is called ciphertext. > Obfuscation is the process of making something more difficult to understand without changing the data itself.

Resources

Encryption is done through advanced algorithms and mathematical operations. This requires a large amount of CPU power and resources.

7.1.5 Symmetric and Asymmetric Encryption Facts

Encryption is the process of encoding data into something that is unreadable called ciphertext. All encryption processes rely on using a unique key. The encryption key is basically a password that is combined with the cipher to encrypt the data. This lesson covers the following topics: > Symmetric encryption > Asymmetric encryption > Hybrid cryptosystems > Ephemeral keys

Encryption keys

Encryption keys are used to encrypt and decrypt data. The key is a string of bits that is randomly generated using a specific cipher, such as Advanced Encryption Standard (AES). There are two types of encryption methods used with keys: symmetric and asymmetric. > Symmetric encryption uses the same key to encrypt and decrypt data. > Asymmetric encryption uses one key to encrypt the data and a different key to decrypt the data. These keys are known as a public key and private key.

Weakness in keys

Encryption keys can be a weakness depending on how they are utilized. > Reuse - Reusing keys is a major concern. The more a key is reused, the more likely it is that it will be cracked. For best security, a key should be used only one time. > Key Length - Encryption keys should be no less than 256 bits. For better security, using an algorithm such as AES that also uses a 128-bit block size is ideal. > Predictability - A predictable key is susceptible to a dictionary attack. Strong keys are completely random. If the number generator used is not random enough, the keys are weaker. This lack of randomness is called entropy. > Longevity - The longer an encryption standard is used, the more likely it is that it will be cracked. Computer scientists are constantly working on newer, more secure methods of encryption.

7.1.13 Cryptographic Attack Facts

Hackers attempt to figure out a way to get to data they want. Encrypting data is usually relatively secure, but there is unfortunately no such thing as a sure thing when it comes to protecting data. By using different types of attacks, hackers might be able to gain access to encrypted data. This lesson covers the following topics: > Common cryptographic attacks > Future of cryptography

Digital Envelope

In addition to digital signatures, data can be protected by using secure data transmission. This protects the message from hackers by using asymmetric encryption to secure the message before sending it to the recipient. Secure data transmission uses the following process: 1. The sender requests a copy of the recipient's public key. 2. The recipient or CA sends a digital certificate containing the public key to the sender. 3. The sender asymmetrically encrypts the message using the recipient's public key. 4. The sender sends the asymmetrically encrypted message to the recipient. 5. The recipient uses his private key to decrypt the message.

Hashing

Hashing is the process of converting one value into another using a mathematical algorithm like MD5 or SHA. This fixed length of data is called the hash. > Hashing is used on data that does not need to be decrypted, such as a password. > When a piece of data is run through a hashing algorithm, it always generates the same hash. If even one letter in a file has been altered, the resulting hash would be different. Because of this, hashing can be used to verify that data has not been altered during transmission. > A hash cannot be decrypted. However, when using hashing for passwords, many online sites have collected massive databases containing a hash for tens of millions (or more) of possible passwords. Once a hash has been captured, it can be compared with the hashes found in the database, quickly resulting in the password used to create the hash.

Hybrid Cryptosystems

Hybrid cryptosystems combine the efficiency of symmetric encryption with the convenience of asymmetric encryption. A hybrid cryptosystem is used as follows: 1. User1 uses their symmetric private key to encrypt some data. 2. User1 then encrypts that symmetric private key using the recipient's public key and sends both to the recipient. 3. User2, the recipient, uses their private key to decrypt User 1's private key which is then used to decrypt the message. 4. As long as User2's private key is kept secret, the data remains secure. > Hybrid cryptosystems are used with many secure communication methods today such as TLS.

International Data Encryption Algorithm (IDEA)

IDEA was first developed in 1991 by James Massey and Xuejia Lai. > IDEA was used in Pretty Good Privacy (PGP) 2.0 and is an optional algorithm in the OpenPGP standard. > IDEA uses a 128-bit key.

Lightweight Cryptography

In 2018, NIST began the process to standardize encryption algorithms called lightweight cryptography. Lightweight cryptography is meant to be used on Internet of Things (IoT) devices. Many IoT devices are small, low-powered devices that don't have the resources to handle other encryption methods. Some of the limitations of IoT devices that lightweight cryptography needs to address are: > Small amount of RAM > Low CPU power > Low powered or runs on batteries Lightweight cryptography algorithms need to work on these devices efficiently while still providing high levels of security.

Ephemeral Keys

In traditional encrypted communications, static keys are used. This means that the same key is used throughout an entire session. The problem with this is that the longer the keys are used, the more susceptible they become to an attack. Ephemeral keys can be used to resolve this issue. Ephemeral keys are keys that are generated for each new session or message sent. For example, perfect forward secrecy (PFC) uses ephemeral keys. Some popular instant messaging apps make use of ephemeral keys to encrypt messages. Each message sent uses a unique key to encrypt it. If a hacker intercepts one key, the rest of the messages are still safe.

Counter Mode (CTR)

Instead of using an initialization vector, CTR uses a nonce combined with a counter that is encrypted. > A nonce is a random string that is used for all blocks during the encryption process. > The encrypted output of the nonce and counter is then XORed with the plaintext to create the ciphertext. > The counter increments for each block. This ensures that each block uses a different value so that even if blocks have the same data, the ciphertext will be different.

Block Cipher

Many symmetric encryption algorithms use the block cipher method. Instead of encrypting our data one bit at a time, a block cipher encrypts the data one chunk at a time. Common block sizes are 64, 128, or 256 bits in length. For example, when encrypting a piece of data that is 100 bytes in size using a 256-bit block size, the data would be encrypted 32 bytes at a time (256 bits/8 = 32 bytes). Because the last block is less than 32 bytes, extra random bits are added to bring the block up to 32 bytes. There are 6 block cipher modes of operation that can be utilized depending on the application or use:

Transactions

Many transactions that currently rely on a paper-based system could benefit from blockchain. For example, a car or house title could be transferred over the blockchain. Because the transactions are transparent, this would create a clear picture of legal ownership.

Digital Signatures

One very common practice that combines cryptographic methods is the digital signature. A digital signature combines the hash of a file and a user's private key to electronically sign a document. This provides authentication and non-repudiation of the file.

Hybrid Models

Operating systems, applications, and other components of information systems typically use a hybrid cryptography system. A hybrid cryptography system combines the strengths of hashing, symmetric encryption, and asymmetric encryption depending on the needs of the project or service. An example of these strengths are: > Use symmetric encryption for fast and efficient encryption of bulk data. > Use hashing to verify message integrity. > Use asymmetric encryption for authentication and non-repudiation. > Use asymmetric encryption for secure exchange of symmetric encryption keys (for example, by encrypting the key used for symmetric encryption prior to sharing the key with the recipient). Using asymmetric cryptography for encryption is best for small pieces of data. A hybrid cryptosystem combines the efficiency of symmetric methods and the convenience of asymmetric methods. One example of this is Microsoft's Encrypting File System, or EFS. Microsoft's EFS uses the following steps to encrypt data: 1. A file is encrypted using a File Encryption Key (FEK). 2. The FEK is encrypted with the user's public asymmetric key. 3. The file is sent to the intended recipient. 4. The user's private key is used to decrypt the FEK. 5. The FEK is used to decrypt the file. One of the biggest weaknesses of the EFS is that the user's private key is essentially their user password. If the password is weak, the encryption will also be weak.

Partially Homomorphic Encryption (PHE)

PHE allows only select simple math functions (such as addition) to be performed. This means that only one math function can be performed an unlimited number of times on the encrypted values.

Above all else, what must be protected to maintain the security and benefit of an asymmetric cryptographic solution, especially if it is widely used for digital certificates?

Private keys The strength of an asymmetric cryptographic system lies in the secrecy and security of its private keys. A digital certificate and a digital signature are little more than unique applications of a private key. If the private keys are compromised for a single user, for a secured network, or for a digital certificate authority, the entire realm of trust is destroyed.

Which of the following can be classified as a stream cipher?

RC4 The most frequently used implementation of symmetric key stream ciphers is Rivest's cipher v4, known as RC4. RC4 uses a variable key up to 256 bits and is commonly used with WEP and SSL. It uses the Key Scheduling Algorithm (KSA) and the Pseudo-Random Generation Algorithm (PRGA). Blowfish, Twofish, and AES are all block ciphers.

Which of the following algorithms are used in asymmetric encryption? (Select two.)

RSA Diffie-Hellman RSA and Diffie-Hellman are asymmetric algorithms. RSA, one of the earliest encryption algorithms, can also be used for digital signatures. The Diffie-Hellman Protocol was created in 1976 but is still in use today in technologies such as SSL, SSH, and IPsec.

Rivest-Shamir-Adleman (RSA)

RSA was developed by Ron Rivest, Adi Shamir, and Leonard Adleman. RSA was released shortly after Diffie-Hellman in 1977. > RSA is still one of the most commonly used algorithms and helped defined the process of using a public key to encrypt data and a private key to decrypt the data. > RSA is used extensively for creating digital signatures.

Diffie-Hellman

Released in 1976 by Whitfield Diffie and Martin Hellman. Its purpose was to allow two users who have never met to safely create a shared key over a public channel such as the internet. Diffie-Hellman is used as follows: 1. The two users agree on two numbers, a prime number (P) and a generator (g). These numbers can be shared publicly. 2. Each user then randomly generates a private number, or key, unique to themselves. 3. Using the prime number, generator, and private key, each user generates a public key using the following formula: > (G^ private number) MOD P 4. The users exchange their public keys which are then used to create a shared secret key using the following formula: > (Shared Public Key^ private number) MOD P 5. Because each public key was generated using the same prime number and generator, each user will come up with the same number for the shared secret key. 6. If a hacker intercepted any of the exchanges, they wouldn't be able to reverse the process without knowing each user's secret number. > Diffie-Hellman is frequently implemented in security protocols such as TLS, IPSec, SSH, and others.

Somewhat Homomorphic Encryption (SHE)

SHE allows more complex math (such as multiplication) to occur. But it can only be performed a limited number of times.

Salt

Salt, or salting the hash, means that a random number of characters are added to the password before the hash is created. For example, if the password to be hashed was p@ssw0rd, a salt, such as E1343135E119C253, may be added. Therefore, the string to be hashed would be p@ssw0rdE1343135E119C253. Since the salt is randomly generated each time, even if the same password is used and is of varying lengths, it's virtually impossible to create a database containing all the possible salted passwords.

Mary wants to send a message to Sam in such a way that only Sam can read it. Which key should be used to encrypt the message?

Sam's public key Sam's public key should be used to encrypt the message. Only the corresponding private key, which only Sam has, can be used to decrypt the message. Mary cannot use Sam's private key because only Sam has that key. Anything encrypted with the private key can be decrypted by anyone with the public key. Encrypting the message using Mary's private key would mean that anyone could read the data using Mary's public key. Encrypting with Mary's public key would mean that only Mary would be able to decrypt it using her private key.

The table below shows some of the more common symmetric key algorithms in use.

See the foillowing:

The following table shows the four main asymmetric encryption algorithms:

See the following:

A receiver wants to verify the integrity of a message received from a sender. A hashing value is contained within the digital signature of the sender. Which of the following must the receiver use to access the hashing value and verify the integrity of the transmission?

Sender's public key Digital signatures are created using the sender's private key. Therefore, only the sender's public key can be used to verify and open any data encrypted with the sender's private key. The recipient's private and public keys are not involved in this type of cryptography situation. Often, the hashing value of a message is protected by the sender's private key (their digital signature). The recipient must extract the original hashing value.

Blockchain Implementations

Sending money isn't the only way blockchain can be used. Some large companies, including Microsoft and IBM, are working to adapt different technologies to the blockchain. The following table describes two types of blockchain implementation.

Which term means a cryptography mechanism that hides secret communications within various forms of data?

Steganography Steganography is the cryptography mechanism that hides secret communications within various forms of data. Ciphertext is the encrypted form of a message that makes it unreadable to all but those the message is intended for. Cryptanalysis is the method of recovering original data that has been encrypted without having access to the key used in the encryption process. A cipher or algorithm is the process or formula used to convert a message or otherwise hide its meaning.

Steganography

Steganography is the technique of hiding or concealing a file, message, image, or video within another file, message, image, or video. Special programs are often used to hide messages in media files. If a hacker intercepts the message, all they see is the media. They don't know that there is a hidden message.

Symmetric Encryption

Symmetric encryption uses the same key to encrypt and decrypt data. This is the simplest and oldest form of encryption. One of the main drawbacks of symmetric encryption is that the key must be shared before a user can decrypt a message. If the key needs to be shared with multiple people, the integrity of the key is compromised as it becomes easier for a hacker to steal the key Symmetric encryption is extremely secure when the key is kept safe. This form of encryption is useful when a large amount of data needs to be encrypted as the encryption process requires less CPU power than other encryption methods.

Data Encryption Standard (DES)

The DES family of ciphers was first developed in the early 1970s by IBM. > DES was heavily used through the 1990s until hackers figured out how to brute-force the keys. > Triple-DES (3DES) was introduced in 1998. This version combined 3 different keys, giving it a key length of 168 bits. > 3DES is extremely CPU heavy and is not used much today.

Rivest's Cipher (RC)

The RC family of algorithms were developed by Ron Rivest in 1987. > RC4 was once the most used cipher. However, many vulnerabilities have since been found and it is no longer supported. > RC6 is the latest version and is a 128-bit cipher.

Common Cryptographic Attacks

The following table covers some of the more common cryptographic attacks.

Future of Cryptography

The future of computers and cryptography lies in quantum computing. Classic computing works by processing bits of 1s and 0s. These bits represent electrical signals, on and off. Quantum computing uses qubits which can exist as both a 1 and 0 at the same time. Quantum computing is exponentially more powerful than today's computing standards. This increased computing power means that today's encryption standards can be hacked easily and quickly. An encryption key that might take years to crack with today's computers can take days or even hours with quantum computers. To combat the inevitable increase of quantum computing, researchers have already started work on post-quantum cryptography. These new methods will be used to ensure the safety of our data in the future.

7.1.2 Cryptography Facts

The goal of all IT security specialists is to keep data safe. Hackers find ways to circumvent firewalls, IPS devices, and other security protocol put in place. Cryptography is one additional layer of defense that can be used to protect data. This lesson covers the following topics: > Cryptography overview > Cryptography concepts > Cryptography methods

Cipher/algorithm

The process or formula used to encrypt a message or otherwise hide the message's meaning.

Plaintext

The readable form of a message.

Cryptography

The science and study of concealing information.

Birthday attack

This attack combines a collision attack and brute-force attack. The name is taken from the birthday probability math problem. The birthday probability math problem states that if you have 30 people in a room, the probability that someone has the same birthday as you is approximately 8%. However, the probability that any two people in the room have the same birthday is 70%. This is because we're not looking for an exact match (just any match), so the probability is higher. Digital signatures can be susceptible to birthday attacks. Generating longer hash outputs is the key to stopping these attacks.

Perfect Forward Secrecy

This cryptography method is used quite often in messaging apps. Instead of the same key being used for an entire conversation or session on a website, each transmission is encrypted with a different unique key.

Fully Homomorphic Encryption (FHE)

This method can handle both simple and advanced math functions (such as addition and multiplication) being performed an unlimited number of times on the encrypted values. FHE is still in the developmental stage.

Output Feedback Mode (OFB)

This mode is identical to CFB except for the IV used after the first round. > The output of the IV encryption is used as the next block's ciphertext.

When a cryptographic system is used to protect data confidentiality, what actually takes place?

Unauthorized users are prevented from viewing or accessing the resource. Cryptography is the science of converting data into a secret code to hide a message's meaning during transmission. Cryptography systems provide the following security services: >Confidentiality by ensuring that only authorized parties can access data. > Integrity by verifying that data has not been altered in transit. > Authentication by proving the identity of the sender or receiver. > Non-repudiation by validating that communications have cone from a particular sender at a particular time.

7.2.2 Cryptography Uses and Limitations Facts

When properly implemented, cryptography methods can be used to support the goals of information security. This is true in all cases except availability. Encryption and decryption can slow the availability of data. This lesson covers the following topics: > Uses of cryptography > Limits of cryptography Uses of Cryptography The following table shows how cryptography can be used to support the goals of Information Security.