CISS 310 Modules 6-7

Define certificate repository (CR) (pg. 194)

*A publicly accessible centralized directory of digital certificates that can be used to view the status of a digital certificate.* The directory can be managed locally by setting it up as a storage area that is connected to the certificate authority (CA) server.

What is a common method to ensure the security and integrity of a CA? (pg. 194)

*By keeping the CA offline from the network*, or AKA offline CA. *It is only brought online when needed for specific and infrequent tasks*, typically limited to the issuance or resistance of certificates authorizing intermediate CAs.

List and describe 5 use cases of cryptography (pg. 161).

*Confidentiality* - Cryptography can protect the confidentiality of information by ensuring that only authorized parties can view it. *Integrity* - Cryptography can protect the integrity of information. Integrity ensures that the information is correct and no unauthorized person or malicious software has altered that data *Authentication* - The authentication of the sender can be verified through cryptography. *Nonrepudiation* - the process of proving that a user performed an action, such as sending an email message *Obfuscation* - making something obscure or unclear. Cryptography can provide a degree of obfuscation by encrypting a file.

Describe the Certificate Life Cycle (pg. 204)

*Creation* - At this stage, the certificate is created and issued to the user. Before the digital certificate is generated, the user must be positively identified. The extent to which the user's identification must be confirmed can vary, depending upon the type of certificate and any existing security policies. Once the user's identification has been verified, the request is sent to the CA for a digital certificate. The CA can then apply its appropriate signing key to the certificate, effectively signing the public key. The relevant fields can be updated by the CA, and the certificate is then forwarded to the registration authority. The CA also can keep a local copy of the certificate it generated. A certificate, once issued, can be published to a public directory if necessary. *Suspension* - This stage could occur once or multiple times throughout the life of a digital certificate if the certificate's validity must be temporarily suspended. Suspension may occur, for example, when employees are on a leave of absence and their digital certificates may not be used for any reason until they return. Upon a user's return, the suspension can be withdrawn or the certificate can be revoked. *Revocation* - At this stage, the certificate is no longer valid. Under certain situations, a certificate may be revoked before its normal expiration date, such as when a user's private key is lost or compromised. When a digital certificate is revoked, the CA updates its internal records, and any CRL with the required certificate information and time stamp (a revoked certificate is identified in a CRL by its certificate serial number). The CA signs the CRL and places it in a public repository so that other applications using certificates can access the repository to determine the status of a certificate. *Expiration* - At the expiration stage, the certificate can no longer be used. Every certificate issued by a CA must have an expiration date. Once it has expired, the certificate may not be used for any type of authentication. The user will be required to follow a process to receive a new certificate with a new expiration date.

Cryptography can provide protection to data as that data resides in which three states? (pg. 161)

*Data in processing* - Data in processing (also called *data in use*) is data on which actions are being performed by devices, such as printing a report from a device. *Data in transit* - Actions that transmit the data across a network, such as an email sent across the Internet, are called data in transit (sometimes called data in motion). *Data at rest* - Data at rest is data stored on electronic media.

List and describe the 4 solutions for key change. (pg. 168)

*Diffie-Hellman (DH)* - The Diffie-Hellman (DH) key exchange requires Alice and Bob to each agree upon a large prime number and related integer. Those two numbers can be made public, yet Alice and Bob, through mathematical computations and exchanges of intermediate values, can separately create the same key. *Diffie-Hellman Ephemeral (DHE)* - Whereas DH uses the same keys each time, Diffie-Hellman Ephemeral (DHE) uses different keys. Ephemeral keys are temporary keys that are used only once and then discarded. *Elliptic Curve Diffie-Hellman (ECDH* - Elliptic Curve Diffie-Hellman (ECDH) uses elliptic curve cryptography instead of prime numbers in its computation. *Perfect forward secrecy* - Public key systems that generate random public keys that are different for each session are called perfect forward secrecy. The value of perfect forward secrecy is that if the secret key is compromised, it cannot reveal the contents of more than one message.

How can you authenticate a person that is requesting a digital certificate can be authenticated by which 3 methods? (pg. 194)

*Email* - In the simplest form, the owner might be identified only by an email address. Although this type of digital certificate might be sufficient for basic email communication, it is insufficient for most other activities. *Documents* - A registration authority can confirm the authenticity of the person requesting the digital certificate by requiring specific documentation such as a birth certificate or a copy of an employee badge that contains a photograph. *In person* - In some instances, the registration authority might require the applicant to apply in person to prove his existence and identity by providing a government-issued passport or driver's license.

A hashing algorithm is secured if it has which following characteristics? Describe them. (pg. 166)

*Fixed size* - A digest of a short set of data should produce the same size as a digest of a long set of data. For example, a digest of the single letter a is 86be7afa339d0fc7cfc785e72f578d33, while a digest of one million occurrences of the letter a is 4a7f5723f954eba1216c9d8f6320431f, the same length. *Unique* - Two different sets of data cannot produce the same digest. Changing a single letter in one data set should produce an entirely different digest. For example, a digest of Sunday is 0d716e73a2a7910bd4ae63407056d79b while a digest of sunday (lowercase s) is 3464eb71bd7a4377967a30da798a1b54. *Original* - It should not be possible to produce a data set that has a desired or predefined hash. *Secure* - The resulting hash cannot be reversed to determine the original plaintext.

Describe the following key handling procedure: renewal (pg. 206)

*Instead of letting a key expire and then creating a new key, an existing key can be renewed.* With renewal, the original public and private keys can continue to be used and new keys do not have to be generated. *However, continually renewing keys makes them more vulnerable to theft or misuse.*

Describe the following key handling procedure: escrow (pg. 206)

*Key escrow refers to a process in which keys are managed by a third party, such as a trusted CA.* In key escrow, the private key is split, and each half is encrypted. The two halves are registered and sent to the third party, which stores each half in a separate location. A user can then retrieve the two halves, combine them, and use the new copy of the private key for decryption. Key escrow relieves users from worrying about losing their private keys. The drawback to this system is that after a user has retrieved the two halves of the key and combined them to create a copy of the key, that copy of the key can be vulnerable to attacks.

List and describe 4 important principles regarding asymmetric cryptography. (pg. 168)

*Key pairs* - Unlike symmetric cryptography that uses only one key, asymmetric cryptography requires a pair of keys. *Public key* - Public keys, by their nature, are designed to be public and do not need to be protected. They can be freely given to anyone or even posted on the Internet. *Private key* - The private key must be kept confidential and never shared. *Both directions* - Asymmetric cryptography keys can work in both directions. A document encrypted with a public key can be decrypted with the corresponding private key. In the same way, a document encrypted with a private key can be decrypted with its public key.

Describe the following key handling procedure: expiration (pg. 206)

*Keys have an expiration date after which they cease to function.* This prevents an attacker, who may have stolen a private key, from being able to decrypt messages for an indefinite period. Some systems set keys to expire after a set period by default.

List and describe 3 common has algorithms. (pg. 166)

*Message Digest (MD)* - One of the earliest hash algorithms is a "family" of algorithms known as Message Digest (MD). Versions of MD hashes were introduced over almost 20 years, from MD2 (1989) to MD6 (2008). The most widely used of these algorithms is MD5. This hash algorithm uses four variables of 32 bits each in a round-robin fashion to create a value that is then compressed. Serious weaknesses have been identified in MD5, and it is no longer considered suitable for use. *Secure Hash Algorithm (SHA)* - Another family of hashes is the Secure Hash Algorithm (SHA). SHA-1 was developed in 1993 but *is no longer considered suitable for use*. SHA-2 has six variations, the most common are SHA-256, SHA-384, and SHA-512 (the last number indicates the length in bits of the digest that is generated) and is currently considered a secure hash. In 2015, after eight years of competition between 51 original entries, SHA-3 was announced as a new standard. One design goal of SHA-3 was to make it dissimilar to previous hash algorithms to prevent threat actors from building on earlier work of compromising the algorithms. *RIPEMD* - it stands for RACE Integrity Primitives Evaluation Message Digest. The primary design feature of RIPEMD is two different and independent parallel chains of computation, the results of which are then combined at the end of the process. All versions of RIPEMD are based on the length of the digest created, including RIPEMD-128, RIPEMD-256, and RIPEMD-320.

List some cryptographic constraints (pg. 163)

*Speed* - The speed at which data can be encrypted or decrypted depends upon several HW and SW factors, and in some instances, a slower speed is unacceptable. *Size* - The resulting size of an encrypted file can be as much as one-third larger than the plaintext. *Weak keys* - Some ciphers can produce a weak key that causes the cipher to behave in unpredictable ways or may compromise overall security. *Key length* - Some ciphers have a short key length, or the number of bits in a key, which results in weaker security. *Longevity* - As computers continue to become more powerful and can "crack" keys, the longevity or useful lifetime of service of ciphers may diminish. *Predictability* - A weak random number generator or PRNG of the cipher may create predictable output. *Reuse* - If someone reuses the same key for each encryption, then it provides a larger data footprint for an attacker to use in attempting to break the encryption. *Entropy* - Entropy is the measure of randomness of a data-generating function, and ciphers with low entropy give the ability to predict future-generated values. *Computational overhead* - Sensors and Internet of Things (IoT) devices often lack the capacity to accommodate the computational overhead for cryptography.

Describe the following key handling procedure: suspension (pg. 206)

*The revocation of a key is permanent; key suspension is for a set period.* For example, if employees are on an extended medical leave, it may be necessary to suspend the use of their keys for security reasons. A suspended key can be later reinstated. As with revocation, the CA should be immediately notified when a key is suspended, and the status of that key should be checked on the CRL to verify that it is no longer valid.

Describe the following key handling procedure: revocation (pg. 206)

*Whereas all keys should expire after a set period, a key may need to be revoked prior to its expiration date.* For example, the need for revoking a key may be the result of an employee being terminated from his position. Revoked keys cannot be reinstated. The CA should be immediately notified when a key is revoked, and then the status of that key should be entered on the CRL.

Describe the following key handling procedure: key destruction (pg. 206)

*you Key destruction removes all private and public keys along with the user's identification information in the CA.* *When a key is revoked or expires, the user's information remains on the CA for audit purposes.*

List the 5 ways a encrypted hardware-based USB device differs from a non-encrypted USB device (pg. 177).

- Encrypted hardware-based USB drives will not connect to a computer until the correct password has been provided. - All data copied to the USB flash drive is automatically encrypted. - The external cases are designed to be tamper-resistant so attackers cannot disassemble the drives. - Administrators can remotely control and track activity on the devices. - Compromised or stolen drives can be remotely disabled.

Describe RSA asymmetric algorithm (pg. 168)

- Published in 1977 The RSA algorithm multiplies two large prime numbers (a prime number is a number divisible only by itself and 1), p and q, to compute their product (n=pq). Next, a number e is chosen that is less than n and a prime factor to (p − 1)(q − 1). Another number d is determined so that (ed − 1) is divisible by (p − 1)(q − 1). The values of e and d are the public and private exponents. The public key is the pair (n,e) while the private key is (n,d). The numbers p and q can be discarded. *The basis of RSA asymmetric encryption security is factoring, or the prime numbers that make up a value. As computers become faster and more powerful, the ability to "crack" RSA asymmetric encryption by computing the factoring has grown.*

Compared with the average energy requirements of a laptop computer (60 watts), the typical wireless sensor draws only ____________. (pg. 163)

0.001 watt

What are the 2 uses of asymmetric cryptography? (pg. 193)

1. Encrypt or decrypt a set of data. 2. Can be used as proof to verify the "signature" of a sender.

What are the 4 requirements of an Extended Validation Certificate (EVC)? (pg. 197)

1. The intermediate CA must pass an independent audit verifying that it follows the EV standards. 2. The existence and identity of the website owner, including its legal existence, physical address, and operational presence, must be verified by the intermediate CA. 3. The intermediate CA must verify that the website is the registered holder and has exclusive control of the domain name. 4. The authorization of the individual(s) applying for the certificate must be verified by the intermediate CA, and a valid signature from an officer of the company must accompany the application.

Describe the 4 steps of a key exchange (pg. 197).

1. The web browser sends a message ("ClientHello") to the server that contains information including the list of cryptographic algorithms that the client supports. 2. The web server responds ("ServerHello") by indicating which cryptographic algorithm will be used. It then sends the server digital certificate to the browser. 3. The web browser verifies the server certificate (such as making sure it has not expired) and extracts the server's public key. The browser generates a random value (called the pre-master secret), encrypts it with the server's public key, and sends it back to the server ("ClientKeyExchange"). 4. The server decrypts the message and obtains the browser's pre-master secret. Because both the browser and server now have the same pre-master secret, they can each create the same master secret. The master secret is used to create session keys, which are symmetric keys to encrypt and decrypt information exchanged during the session and to verify its integrity.

What are two methods that can be used to check if a certificate has been revoked? (pg. 194)

1. Use a Certification Revocation List (CRL) - a list of certificate serial numbers that have been revoked 2. Online Certificate Status Protocol (OCSP) - performs a real-time lookup of a certificate's status.

As of mid-2020, Microsoft Windows recognized ____ trusted root CAs while Apple recognized _______ for all of its OS versions and one "always ask" root CA, which is ___________________. (pg. 197)

82 115 untrusted but not blocked

Two Rights and a Wrong, select the wrong answer and explain. (pg. 197) A. A digital certificate is a technology used to associate a user's identity to a public key and that has been digitally signed by the owner of the private key. B. A certificate repository (CR) is a publicly accessible centralized directory of digital certificates that can be used to view the status of a digital certificate. C. Root digital certificates are self-signed.

A A digital certificate is a technology used to associate a user's identity to a public key and *that has been digitally signed by a trusted third party.*

Describe hash algorithm (pg. 166).

A *hash algorithm* creates a unique "digital fingerprint" of a set of data. This process is called *hashing*, and the resulting fingerprint is a *digest* (sometimes called a message digest or hash) that represents the contents. Hashing is used primarily for *comparison purposes.*

Define and describe lightweight cryptography (pg. 163)

A category of cryptography that has fewer features and is less robust than normal cryptography. Lightweight cryptography has the goal of providing cryptographic solutions uniquely tailored to low-power devices that need to manage resource vs. security constraints. However, *lightweight cryptography is not a weakened cryptography* but may simply have fewer features and be less robust than normal cryptography.

Define offline certificate authority (pg. 194)

A certificate authority that is not directly connected to a network.

Define and describe certificate practice statement (CPS)

A certificate practice statement (CPS) is a more technical document than a CP. A CPS describes in detail how the CA uses and manages certificates. Additional topics for a CPS include how users register for a digital certificate, how to issue digital certificates, when to revoke digital certificates, procedural controls, key pair generation and installation, and private key protection.

Define email digital certificate (pg. 197).

A certificate that allows a user to digitally sign and encrypt mail messages.

Define root digital certificate (pg. 197).

A certificate that is created and verified by a certificate authority (CA).

Define Extended Validation Certificate (EVC) (pg. 197)

A certificate that requires *more extensive verification of the legitimacy of the business* than a domain validation digital certificate.

Define machine/computer digital certificate and provide an example (pg. 197).

A certificate used to verify the identity of a device in a network. For example, a printer may use a machine digital certificate to verify to the endpoint that it is an authentic and authorized device on the network.

How are checksum and hashing different? (pg. 166)

A checksum is intended to verify (check) the integrity of data and identify data-transmission errors, while a hash is designed to create a unique digital fingerprint of the data.

Define a block cipher (pg. 164).

A cipher that manipulates an entire block of plaintext at one time. The plaintext message is divided into separate blocks of 8 to 16 bytes, and then each block is encrypted independently. For additional security, the blocks can be randomized.

Define quantum computer and explain why it's so powerful.

A computer that relies on quantum physics using atomic-scale units (qubits) that can be 0 and 1 at the same time. As a result, one qubit can carry out two separate streams of calculations simultaneously, meaning that quantum computers will be much faster and more efficient than today's computers.

Describe a one-time pad (OTP) (pg. 164).

A cryptographic algorithm that combines plaintext with a random key. A pad is a long sequence of random letters. The letters are combined with the plaintext message to produce the ciphertext. To decipher the message, the recipient must have a copy of the pad to reverse the process.

Define weak key (pg. 163)

A key that causes the cipher to behave in unpredictable ways or may compromise overall security.

What is a Certification Revocation List (CRL)? (pg. 194)

A list of certificate serial numbers that have been revoked. Many certificate authorities (CAs) maintain an online CRL that can be queried by entering the certificate's serial number. In addition, a local computer receives updates on the status of certificates and maintains a local CRL.

Define key in the context of cryptography (pg. 159)

A mathematical value entered into the algorithm to produce the ciphertext.

Define file system (pg. 176).

A method used by an OS to store, retrieve, and organize files. Protecting individual files or multiple files through file system cryptography can be performed using third-party software or OS cryptographic features.

Define and describe certificate policy

A published set of rules that govern the operation of a PKI. The CP provides recommended baseline security requirements for the use and operation of CA, intermediate CA, and other PKI components. A CP should cover such topics as CA or intermediate CA obligations, user obligations, confidentiality, operational requirements, and training.

Define quantum key distribution (QKD)

A secure communication method which implements a cryptographic protocol involving components of quantum mechanics. It enables two parties to produce a shared random secret key known only to them, which can then be used to encrypt and decrypt messages.

What is Opal? (pg. 177)

A set of specifications for SEDs developed by the Trusted Computing Group (TCG) SEDs that support Opal use hardware encryption technology to secure data stored in them. Opal also ensures the interoperability of SEDs among vendors.

Describe sponge function (pg. 164).

A sponge function takes as input a string of any length and returns a string of any requested variable length. This function repeatedly applies a process on the input that has been padded with additional characters until all characters are used (absorbed in the sponge).

Define and describe quantum communication.

A subcategory of quantum cryptography used to secure telecommunications.

What is a Certificate Signing Request? (pg. 194)

A user request for a digital certificate.

Define and describe a Subject Alternative Name (SAN) digital certificate (pg. 197).

Also known as a Unified Communications Certificate (UCC), is primarily used for Microsoft Exchange servers or unified communications (the integration of different types of electronic communication such as email, SMS text messaging, and fax). The certificate allows multiple server or domain names to use the same secure certificate by associating different values with the certificate.

What is the physical difference between an HSM and TSM? (pg. 177)

An *HSM is external* while a *TPM is internal.*

Describe pseudorandom number generator (PRNG). (pg. 159)

An algorithm for creating a sequence of numbers whose properties approximate those of a random number. PRNGs attempt to create numbers that are as random as possible.

Define a stream cipher (pg. 164).

An algorithm that takes one character and replaces it with another.

Describe Elliptic Curve Cryptography (ECC) (pg. 168)

An algorithm that uses elliptic curves instead of prime numbers to compute keys. With ECC, users share one elliptic curve and one point on the curve. One user chooses a secret random number and computes a public key based on a point on the curve; the other user does the same. They can now exchange messages because the shared public keys can generate a private key on an elliptic curve.

Describe a downgrade attack (pg. 174).

An attacker that forces the system to abandon the current higher security mode of operation and instead "fall back" to implementing an older and less secure mode. The threat actor can then attack the weaker mode.

What is a registration authority? (pg. 194)

An authority responsible for verifying the credentials of the applicant for a digital certificate.

Describe Digital Signature Algorithm (DSA) (pg. 168)

An electronic signature is *an electronic verification of a sender*. It has the following benefits: - Verify the sender: A digital signature serves to confirm the identity of the person from whom the electronic message originated. - Prevent the sender from disowning the message. The signer cannot later attempt to disown it by claiming the signature was forged (nonrepudiation). - Prove the integrity of the message. A digital signature can prove that the message has not been altered since it was signed. The Digital Signature Algorithm (DSA) is a U.S. federal government standard for digital signatures. DSA was proposed by NIST in 1991 for use in their Digital Signature Standard (DSS). Although patented, NIST has made the patent available worldwide royalty-free. The standard continues to be revised and updated periodically by NIST.

What is an intermediate certificate authority (CA)? (pg. 194)

An entity that processes the CSR (Certificate Signing Request) verifies the authenticity of the user on behalf of a certificate authority (CA) and issues a digital certificate.

What is quantum computing's drawback in terms of cybersecurity?

Asymmetric cryptography begins by multiplying two prime numbers, a strong method because it is difficult for today's computers to determine the prime numbers that make up the value (factoring). *However, a single quantum computer could perform factoring by using hundreds of atoms in parallel to quickly factor huge numbers*, rendering virtually all current asymmetric cryptographic algorithms useless.

Two Rights and a Wrong, select the wrong answer and explain. (pg. 179) A. Modern OSs provide encryption support natively. B. Opal is a standard for FEDs. C. An HSM is external while a TMP is internal.

B. Opal is standard for SEDs.

Two Rights and a Wrong, select the wrong and explain. (pg. 168) A. A digest of a short set of data should produce the same size as a digest of a long set of data. B. SHA-1 is considered a secure hash algorithm. C. Asymmetric cryptography keys can work in both directions.

B. SHA-1 is *no longer* considered a secure hash algorithm.

Two Rights and a Wrong, select the wrong and explain. (pg. 163) A. Steganography hides the existence of information. B. Unencrypted data that is input for encryption or is the output of decryption is called cleartext. C. Entropy is the measure of randomness of a data-generating function.

B. Unencrypted data that is input for encryption or is the output of decryption is called cleartext. False, unencrypted data that is input for encryption or is the output of decryption is called *plaintext.* *Cleartext* is unencrypted data that is not intended to be encrypted.

X.509 certificates have three encoding formats (layouts). List them. (pg. 197)

Basic Encoding Rules (BER) Canonical Encoding Rules (CER) Distinguished Encoding Rules (DER). The X.509 certificates themselves can be contained within different file formats.

Why would mobile devices use ECC? (pg. 168)

Because mobile devices are limited in terms of computing power due to their smaller size, ECC offers security that is comparable to other asymmetric cryptography but with smaller key sizes, resulting in faster computations and lower power consumption.

Describe blowfish (pg. 167)

Blowfish is a block cipher algorithm that operates on 64-bit blocks and can have a key length from 32 to 448 bits. To date, no significant weaknesses have been identified. A later derivation of Blowfish known as Twofish is also considered a strong algorithm, although it has not been used as widely as Blowfish.

Two Rights and a Wrong, select the wrong answer and explain. (pg. 175) A. In a downgrade attack, an attacker forces the system to abandon the current higher security mode of operation and instead "fall back" to implementing an older and less secure mode. B. Post-quantum cryptography is comprised of algorithms that are secure against an attack by a quantum computer. C. The basis of a quantum computer is a bit.

C The basis of a quantum computer is a qubit.

Two Rights and a Wrong, select the wrong answer and explain. (pg. 206) A. The hierarchical trust model assigns a single hierarchy with one master CA called the root. B. An OID, which names an object or entity, corresponds to a node in a hierarchy tree structure. OIDs can name every object type in an X.509 certificate. C. When a digital certificate is revoked, the user must update internal records and any CRL with the required certificate information and timestamp.

C When a digital certificate is revoked, *the CA updates its internal records* and any CRL with the required certificate information and time stamp.

Define a domain validation digital certificate (pg. 197).

Certificate that verifies the identity of the entity that has control over the domain name.

Define a code signing digital certificate (pg. 197).

Certificates used by software developers to digitally sign a program to prove that the software comes from the entity that signed it and no unauthorized third party has altered or compromised it.

Define algorithm in the context of cryptography. Provide a synonym. (pg. 159)

Consists of a procedure based on a mathematical formula used to encrypt and decrypt the data. cipher

Define post-quantum cryptography

Cryptographic algorithms that are secure against an attack by a quantum computer.

What cryptographic algorithm effectively catapulted the study of cryptography into the public arena? (pg. 167)

Data Encryption Standard - DES

List 5 common symmetric cryptographic algorithms (pg. 167).

Data Encryption Standard - DES Triple Data Encryption Standard - 3DES Advanced Encryption Data Standard - AEDS Rivest Cipher - RC Blowfish

Define asymmetric cryptographic algorithms and provide a synonym (pg. 168).

Definition: Cryptography that uses two mathematically related keys. They keys can work in both direction. Description: *Asymmetric encryption uses two keys instead of only one.* The keys are mathematically related and are known as the public key and the private key. *The public key is known to everyone and can be freely distributed, while the private key is known only to the individual to whom it belongs.* public key cryptography

What should you do with expired keys (pg. 206)?

Destroy them

What two techniques can be added to a cryptographic algorithm to thwart known ciphertext attacks? (pg. 174)

Diffusion and confusion Diffusion changes a single character of plaintext into multiple characters of ciphertext, while confusion makes each character of the ciphertext based upon several parts of the key.

Describe certificate revocation (CR) (pg. 194).

Digital certificates normally have an expiration date. However, in some circumstances, the certificates are revoked before they expire. Some reasons might be benign, such as when a certificate is no longer used or the details of the certificate—such as the user's address—have changed. Other circumstances could be more dangerous. For example, if attackers steal a user's private key, they could impersonate the victim by using digital certificates without other users being aware of the impersonation. In addition, what would happen if digital certificates were stolen from a certificate authority (CA)? The thieves could issue certificates to themselves that would be trusted by unsuspecting users. The CA must publish lists of approved certificates as well as revoked certificates in a timely fashion so that security is not compromised.

What is the primary weakness of symmetric cryptographic algorithms (pg. 168)?

Distributing and maintaining a secure single key among multiple users, who are often scattered geographically, poses significant challenges.

Define and describe self-encrypting devices (pg. 177).

Drives that can automatically encrypt any data stored on them. When the computer or other device with an SED is *initially powered up*, the drive and the host device *perform an authentication process*. If the authentication process fails, the drive can be configured to simply deny any access to the drive or even perform a cryptographic erase on specified blocks of data. (A cryptographic erase deletes the decryption keys so that no data can be recovered.) It is also impossible to install the drive on another computer to read its contents.

All modern OSs and web browsers rely on ____________ (pg. 168).

ECC

What is more secure - RSA or ECC? (pg. 168)

ECC

Describe the web of trust model (pg. 203).

Each user signs a digital certificate and then exchanges certificates with all other users. Because all users trust each other, each user can sign the certificate of all other users.

What is the name of Window's native encryption? (pg. 176)

Encrypting File System (EFS) is a cryptography system for Windows releases that use the Windows NT file system (NTFS)

Define symmetric cryptographic algorithms (pg. 167).

Encryption that uses a single key to encrypt and decrypt a message.

Describe substitution cipher. (pg. 159)

Exhcnages one character for another. Example: A = 1, B = 2, and so on.

Define certificate attributes and list them (pg. 197).

Fields in an X.509 digital certificate that are used when parties negotiate a secure connection. Attributes that must be included are the certificate validity period, end-host identity information, encryption keys that will be used for secure communications, the signature of the issuing CA, and the common name (CN).

What is the name of Apple's native encryption? (pg. 176)

FileVault

List and describe the 3 ways approved root digital certificates and intermediate certificates are distributed. (pg. 197)

First, they can be distributed through updates to the OS. Second, they can be distributed through updates to the web browser. At one time, browsers relied on the underlying OS-approved list, but today they rely on their own browser updates. Web browser certificate chaining and root digital certificates can be seen in the browsers and are illustrated in Figure 7-5. A third option is pinning, in which a digital certificate is hard-coded (pinned) within the app (program) that is using the certificate. Pinning is common for securing mobile messaging apps and for certain web-based services and browsers.

Define the birthday paradox (pg. 174).

For someone in a given room to have a 50 percent chance of sharing your birthday, 253 people would need to be in the room. It is much harder to find something that collides with a specific hash than it is to find two inputs that hash to the same value.

List 4 different third-party tools that can be used for encryption (pg. 176).

GNU Privacy Guard (which is abbreviated GNuPG) AxCrypt Folder Lock VeraCrypt

Define steganography (pg. 159)

Hiding the existence of data within another type of file, such as an image file.

What are advantages of using separate intermediate CAs? (pg. 194)

If many entities require a digital certificate, or if these are spread out across geographical areas, using a single centralized CA could create bottlenecks or inconveniences. Using multiple intermediate CAs, who can "off-load" the registration functions, can create an improved workflow. The process works because the CAs trust the intermediate CAs.

What are limitation of a hierarchical trust model on a larger scale? (pg. 203)

If the CA's single private key were compromised, then all digital certificates would be worthless. Also, having a single CA who must verify and sign all digital certificates may create a significant backlog.

Explain this statement: Determining the revocation status of certificates presented by websites is an ongoing problem in web security. (pg. 194)

Initially, modern web browsers (Chrome, Firefox, Internet Explorer, Safari, and Opera) used OCSP. However, if the web browser cannot reach the OCSP Responder server, such as when the server is down, then the browser receives a network error message (called a soft fail), and the revocation check is simply ignored. Also, online revocation checking by web browsers can be slow. For these reasons, web browsers have implemented a range of solutions to reduce or eliminate the need for online revocation checking by instead "harvesting" lists of revoked certificates from CAs and then pushing them to the user's browser.

Define/describe the hierarchical trust model (pg. 203).

It assigns a single hierarchy with one master CA called the root. The root signs all digital certificate authorities with a single key. (A hierarchical trust model is illustrated in Figure 7-9.)

According to Microsoft, what are the benefits of a topological approach in quantum computing?

It can help a quantum computer run algorithms more reliably, with fewer risks of temperature or noise impacting the accuracy of a calculation or even preventing the calculation from being completed.

What is a drawback to software based storage of keys? (pg. 206)

It can leave keys open to attacks: vulnerabilities in the client operating system, for example, can expose keys to attackers.

What does a digital signature *not* do? (pg. 168)

It does not encrypt a message.

A digital signature has a weakness: while it can only prove the owner of the private key, it cannot do what? (pg. 193)

It does not necessarily confirm the true identity of the sender. That is, a digital signature only shows that the private key of the sender was used to encrypt the digital signature, but it does not definitively prove who was the sender of that key. *If Alice receives a message with a digital signature claiming to be from Bob, she cannot know for certain that it is the real Bob whose public key she is retrieving.*

Describe Rivest Cipher (RC) (pg. 167)

It is a family of six algorithms. RC4, the most common RC cipher, is a stream cipher that accepts keys up to 128 bits in length.

Define and describe a Hardware Security Module (HSM) (pg. 177).

It is a removable external cryptographic device. An HSM can be a USB device, an expansion card, a device the connects directly to a computer through a port, or a secure network server. An HSM includes an onboard random number generator and key storage facility, as well as accelerated symmetric and asymmetric encryption, and can even back up sensitive material in encrypted form. Because the security is based on hardware and not through software, malware cannot compromise it.

Define and describe blockchain

It is a shared, immutable (cannot be changed) ledger that facilitates the processing of recording transactions and tracking assets in a business network. At a high level, blockchain technology allows a network of computers to agree at regular intervals on the true state of a distributed ledger. It is a system in which a record of transactions made is maintained across several computers that are linked in a peer-to-peer network.

Describe Advanced Encryption Standard (AES) (pg. 167)

It is a symmetric algorithm that performs three steps on every block (128 bits) of plaintext. Within step 2, multiple rounds are performed depending upon the key size: a 128-bit key performs nine rounds, a 192-bit key performs 11 rounds, and a 256-bit key, known as AES-256, uses 13 rounds. Within each round, bytes are substituted and rearranged, and then special multiplication is performed based on the new arrangement. *To date, no attacks have been successful against AES.*

Define digital certificate (pg. 193).

It is a technology used to associate a user's identity to a public key and that has been digitally signed by a trusted third party. The third party verifies the owner and that the public key belongs to that owner.

Describe XOR cipher (pg. 159)

It is based on the binary operation eXclusive OR to compare two bits: if the bits are different, a 1 is returned, but if they are identical, then a 0 is returned.

What is the purpose of hashing? (pg. 166)

It is intended to be one-way in that its digest cannot be reversed to reveal the original set of data (plaintext). It is also used to verify that the original contents of an item have not been changed.

Describe ROT13 (pg. 159)

It is is an example of a substitution cipher where the entire alphabet is rotated 13 steps, A = N, B = O, and so on.

Define and describe a wildcard digital certificate. (pg. 197)

It is used to validate a main domain along with all subdomains. For example, a domain validation digital certificate for www.example.comwould only cover that specific site. A wildcard digital certificate for *. example.com would cover www.example.com, mail.example.com, ftp.example.com, and any other subdomains.

What is an Online Certificate Status Protocol (OCSP)? (pg. 194)

It performs a real-time lookup of a certificate's status. OCSP is called a request-response protocol. The browser sends the certificate's information to a trusted entity like the certificate authority (CA), known as an OCSP Responder. The OCSP Responder then provides revocation information on that one specific certificate.

Describe how steganography works today (pg. 159)

It typically takes the data, divides it into small pieces, and then hides the pieces among invisible parts of the file. A common scheme is to hide data in the file header fields that describe the file, between sections of the metadata (data that is used to describe the content or structure of the actual data), or in the areas of a file that contain the content itself.

Describe Triple Data Encryption Standard (3DES) (pg. 167)

It was designed to replace DES. As its name implies, 3DES uses three rounds of encryption instead of just one. The ciphertext of one round becomes the entire input for the second iteration. 3DES employs a total of 48 iterations in its encryption (3 iterations × 16 rounds). The most secure versions of 3DES use different keys for each round, as shown in Figure 6-6 (e-book). Although 3DES addresses several of the key weaknesses of DES, *it is no longer considered the most secure symmetric cryptographic algorithm.*

Describe the following symmetric cryptographic algorithm: Data Encryption Standard - DES (pg. 167)

It was one of the first widely used symmetric cryptography algorithms. The U.S. government officially adopted DES as the standard for encrypting unclassified information. Although DES *was once widely implemented, it is no longer considered suitable for use.*

Define and describe certificate chaining (pg. 197).

Linking several certificates together to establish trust between all certificates involved. Certificate chaining creates a path between the trusted root certificate authorities (CAs) (of which there are a few) and intermediate CAs (of which there are many) with the digital certificates that have been issued. Every certificate is signed by the entity that is identified by the next-higher certified entity in the chain. In this way, the trust of a certificate can be traced back to the highest level of CA.

What is one method of decreasing latency? What is the limitation of doing so? (pg. 163)

Make the cryptographic algorithm run faster. It increases power consumption.

Describe attacks based on misconfiguration (pg. 174).

Most breaches of cryptography are the result of incorrect choices or misconfigurations of the cryptography options, known as misconfiguration implementation. Selecting weak algorithms, such as DES or SHA-1, should be avoided since they are no longer secure. Many cryptographic algorithms have several configuration options, and unless careful consideration is given to the options during setup, the cryptography may be improperly implemented. Careless users can also weaken cryptography if they choose SHA-256, for example, when a much stronger SHA3-512 is available through a simple menu choice.

Define and describe the distributed trust model (pg. 203).

Multiple CAs sign digital certificates. This essentially eliminates the limitations of a hierarchical trust model. The loss of a CA's private key would compromise only those digital certificates it had signed, and the workload of verifying and signing digital certificates can be distributed. In addition, CAs can delegate authority to other intermediate CAs to sign digital certificates. *The distributed trust model is the basis for most digital certificates used on the Internet.*

How do modern OSs provide encryption? (pg. 176)

Natively

Is hashing used to create ciphertext that can later be decrypted? (pg. 166)

No

Should you share keys in plaintext (pg. 206)?

No

Can obfuscation be used as a general cybersecurity protection on its own? Why or why not? Explain. (pg. 161)

No Because it is essentially impossible to keep secrets from everyone, eventually the data will be discovered and the security compromised.

Does a domain validation digital certificate indicate the trustworthiness of the individuals behind the site? (pg. 197)

No, it only verifies who has control of that domain.

Define and describe high resiliency in the context of cryptography. (pg. 163)

Not all constraints prevent a device from using cryptography, sometimes it simply slows down the device. Therefore, the cryptography much have high resiliency - the ability to quickly recover from these constraints.

What is OCSP stapling? (pg. 194)

OCSP requires the OCSP Responder to provide responses to every web client of a certificate in real time, which may create a high volume of traffic. With OCSP stapling, web servers send queries to the Responder OCSP server at regular intervals to receive a signed time-stamped OCSP response. When a client's web browser attempts to connect to the web server, the server can include (staple) in the handshake with the web browser the previously received OCSP response. The browser then can evaluate the OCSP response to determine if it is trustworthy.

How many times can one use a on-time pad (OTP)? (pg. 164).

One can use it multiple times, but one *should only use it once*.

Define and describe perfect forward secrecy (pg. 168).

Public key systems that generate random public keys that are different for each session are called perfect forward secrecy. The value of perfect forward secrecy is that if the secret key is compromised, it cannot reveal the contents of more than one message.

Define third-party trust (pg. 203).

Refers to a situation in which two individuals trust each other because each trusts a common third party.

Blockchain relies on which type cryptographic hash algorithms to record transactions?

SHA-256

Should a public or private key be used? (pg. 168)

See Table 6-6 on pg. 168

Define low-power device (pg. 163)

Small electronic devices that consume small amounts of power.

How could a state actor use a stolen digital certificate? (pg. 194)

State actors have also been charged with stealing digital certificates to trick their own citizens into connecting with a fraudulent email site to monitor their messages and to locate and crackdown on dissidents.

_____________________ is sometimes used together with encryption so that the information is doubly protected. Explain (pg. 159)

Steganography First encrypting the data and then hiding it requires someone seeking the information to first find the data and then decrypt it.

Which is more secure: a block cipher or sponge function? Explain why. (pg. 164)

Stream ciphers are less secure because the engine that generates the stream does not vary; the only change is the plaintext itself. Block ciphers are considered more secure because the output is more random, as the cipher is reset to its original state after each block is processed.

Describe the bridge trust model (pg. 203).

The bridge trust model is similar to the distributed trust model in that no single CA signs digital certificates. However, with the bridge trust model, *one CA acts as a facilitator to interconnect all other CAs.* *The facilitator CA does not issue digital certificates; instead, it acts as the hub between hierarchical trust models and distributed trust models, linking the models together.*

Define and describe the Trusted Platform Module (TPM) (pg. 177).

The chip on a motherboard that provides cryptographic services. For example, TPM *includes a true random number generator* instead of a PRNG as well as *full support for asymmetric encryption. TPM can also generate public and private keys.* Also, TPM can measure and test key components as the computer is starting up. It will prevent the computer from booting if system files or data have been altered. With TPM, if the hard drive is moved to another computer, the user must enter a recovery password before gaining access to the system volume.

What is a certificate authority? (pg. 194)

The entity responsible for digital certificates.

What is the common name (CN)? (pg. 197)

The name of the device protected by the digital certificate.

Define cryptography and how it is usually accomplished. (pg. 159)

The practice of transforming information so that it is secure and cannot be understood. by unauthorized persons. Through scrambling the information so that only approved recipients (human or machine) can read it.

Define decryption (pg. 159)

The process of changing encrypted text into the original text.

Define encyrption (pg. 159)

The process of changing original text into a scrambled message.

Define and describe the purpose of nonrepudiation in the context of cryptography (pg. 161).

The process of proving that a user performed an action, such as sending an email message. Nonrepudiation prevents an individual from fraudulently reneging on an action. The nonrepudiation features of cryptography can prevent managers from claiming they never sent lists of employees to be laid off to an unauthorized third party.

Define ciphertext (pg. 159)

The scrambled and unreadable output of encryption.

Define Public Key Infrastructure (PKI) (pg. 202.5)

The underlying infrastructure for the management of public keys used in digital certificates.

Describe Known Ciphertext attacks (pg. 174).

The use of sophisticated statistical tools to analyze he ciphertext and discover a pattern, which may be useful in figuring out the plaintext or key.

What is the endpoint of a certificate chain? (pg. 197)

The user digital certificate

Why are wireless data networks particularly susceptible to known ciphertext attacks? (pg. 174)

Threat actors can capture large sets of ciphertexts to analyze and then inject their own frames into the wireless transmissions.

List 3 real-world applications where ECC is used? (pg. 168)

Tor US government to protect internal communications a mechanism to prove ownership of bitcoins

Define collision and describe a collision attack (pg. 174).

Two files having the same digest. A collision attack is an attempt to find two input strings of a hash function that produce the same hash result.

Define plaintext (pg. 159)

Unencrypted data that is input for encryption or is the output of decryption.

Define cleartext (pg. 159)

Unencrypted data that is not intended to be encrypted.

Describe the following key handling procedure: recovery (pg. 206)

What happens if employees are hospitalized, and their organization needs to transact business using their keys? Some CA systems have an embedded key recovery system that designates a *key recovery agent (KRA), a highly trusted person responsible for recovering lost or damaged digital certificates.* Digital certificates can then be archived along with a user's private key. If the user is unavailable or if the certificate is lost, the certificate with the private key can be recovered. *Another technique is known as M-of-N control*. A user's private key is encrypted and divided into a specific number of parts, such as three. The parts are distributed to other individuals with an overlap, so multiple individuals have the same part. For example, the three parts could be distributed to six people, with two people each having the same part. This is known as the N group. If it is necessary to recover the key, a smaller subset of the N group, known as the M group, must meet and agree that the key should be recovered. If a majority of the M group can agree, they can then piece the key together. M-of-N control is illustrated in Figure 7-12. *The reason for distributing parts of the key to multiple users is that the absence of one member would not prevent the key from being recovered.*

Describe full disk encryption (FDE) and provide an example (pg. 176).

When cryptography is applied to an entire disk, it therefore protects all data on a hard drive. One example of full disk encryption software is that included in Microsoft Windows known as BitLocker drive encryption software. BitLocker encrypts the entire system volume, including the Windows Registry and any temporary files that might hold confidential information. BitLocker prevents attackers from accessing data by booting from another OS or placing the hard drive in another computer.

Fill in the blanks: The standard format for digital certificates is _________. The format was first introduced more than 20 years ago and was adapted for Internet use. The current version is ____________. Digital certificates following this standard can be read or written by any hardware device or application that follows the __________ format. (pg. 197)

X.509 Version 3 X.509

Can a CA have more than one intermediate CA? (pg. 194)

Yes

Do digital certificates normally have an expiration date? (pg. 194)

Yes

Can digital certificates be used to authenticate the authors of documents? (pg. 197)

Yes For example, a user can create a Microsoft Word or Adobe Portable Document Format (PDF) document and then use a digital certificate to create a digital signature.

Define direct trust (pg. 203).

a relationship exists between two individuals because one person knows the other person

What are the two most common types of attacks against cryptography? (p.g 174)

algorithm attacks and collision attacks

X.509 certificates can either be contained in a ____________ file with a .cer extension or in a _______________ file, which is a binary-to-text encoding scheme that presents binary data in ASCII string format. (pg. 197)

binary Base64

What trust model involves linking federal and state governments (pg. 203).

bridge trust model

When cryptographic algorithms are used in networks, what are they called? (pg. 208)

cryptographic protocols

What is viewed as a necessary feature to add to protect low-power devices and applications that require fast response times to make them secure. (pg. 163)

cryptography

The CN can reference a single ________________ or ___________ devices with a wildcard certificate (*. example.com) but is not the __________________. (pg. 197)

device (www.example.com) multiple URL (https://example.com)

When Bob sends a message to Alice, he does not ask her to retrieve his public key from a central site. Instead, Bob attaches the _________________ to the message. (pg. 193)

digital certificate

In short, PKI is what? (pg. 203)

digital certificate management

To address the security of web server digital certificates, there are several types of domain digital certificates. List them. (pg. 197)

domain validation digital certificates extended validation digital certificates wildcard digital certificates subject alternative names digital certificates.

Public keys can be stored by ____________________________________, while private keys can be stored on _____________________________. (pg. 206)

embedding them within digital certificates the user's local system

If more security is needed than a single set of public and private keys, multiple pairs of dual keys can be created. One pair of keys may be used to _____________________, and the public key can be backed up to another location. The second pair would be used only for ___________________, and the public key in that pair would _______________________ (pg. 206).

encrypt information digital signatures never be backed up

PKI is a ___________________ for the _________________- of all the elements involved in digital certificates for digital certificate management... to create, store, distribute, and revoke digital certificates (pg. 203).

framework administration

Storing keys in __________________ is an alternative to software-based storage. For storing public keys, special _____________ and ________________________ can be used. Private keys can be stored on smart cards or in tokens. (pg. 206)

hardware CA root intermediate CA hardware devices

What are the three broad categories of cryptographic algorithms? (pg. 164)

hash algorithms symmetric cryptographic algorithms asymmetric cryptographic algorithms

In addition to protecting data in processing and at rest, cryptographic algorithms are most often used to protect data ____________________________________________. (pg. 208)

in transit or motion across a network

What makes cryptography secure is the obscurity of the _________________ and not of the ________________. (pg. 161)

key algorithm

While for hash algorithms that produce _____________________ such as __________________ the odds of such a collision are very low, yet for hash algorithms that produce ___________________, such as _________, the odds increase (pg. 174).

long digests, SHA3-512 shorter digests, MD5

At its essence, cryptography replaces trust with _________________________. (pg. 159)

mathematics

Where can private keys can be stored (pg. 206)?

on smart cards or in tokens

What information is included in a digital certificate? (pg. 193)

owner's name or alias the owner's public key the digital signature of the issuer the serial number of the digital certificate expiration date of the public key It can contain other user-supplied information, such as an email address, postal address, and basic registration information.

Stopped reading at....

pg. 208 :(

What is another name for symmetric encryption? (pg. 167)

private key cryptography

One of the important management tools for the use of digital certificates and asymmetric cryptography is _____________________________.

public key infrastructure

Digital certificates can be grouped into which 4 broad categories? (pg. 197)

root certificates domain certificates and hardware and software certificates In addition there are standardized certificate formats and attributes.

List 3 hardware encryption options that are considered to be sophisticated (pg. 177).

self-encrypting drives trusted platform module hardware security module

Because a CA has no higher-level authority, root digital certificates are ____________________ and do not _____________________________. (pg. 197)

self-signed depend upon a higher-level authority for authentication

Many network devices can create their own what? (pg. 197)

self-signed machine digital certificates

What were the original cryptographic algorithms for encrypting and decrypting data? (pg. 167)

symmetric cryptographic algorithms

Because domain validation digital certificates are not verifying the identity of a person but only ______________________, they often can be generated automatically and are very inexpensive or even free. (pg. 197)

the control over a site

List the 3 PKI models that use a CA (pg. 203).

the hierarchical trust model the distributed trust model the bridge trust model

Symmetric cryptography can provide strong encryption — if what is done? (pg. 167)

the key is kept secure between the sender and all the recipients

No user other than _________________ must ever have the private key. (pg. 168)

the owner

Define trust model (pg. 203) (pg. 203).

the type of trust relationship that can exist between individuals or entities

Web server digital certificates perform two primary functions. What are they? (pg. 197)

they ensure the authenticity of the web server to the client the authenticity of the cryptographic connection to the web server

In reality, proprietary algorithms are _______________. Explain your answer. (pg. 161)

weak *Modern cryptographic algorithms are based on known mathematical proofs,* and the algorithms are selected by competition after having been thoroughly reviewed by the cryptographic community. The algorithms have proven their value over time by their wide adoption and use. Proprietary algorithms, on the other hand, have not been properly vetted and will likely contain flaws and, thus, should not be used.

A less secure trust model that uses no third party is called the ______________________ model and is based on ____________________ (pg. 203).

web of trust direct trust

Most digital certificates are __________________ digital certificates that are issued from a(n) __________________________. (pg. 197)

web server web server to an endpoint