Chapter 8 Principles of Information Security

Symmetric encryption

A cryptographic method in which the same algorithm and secret key are used both to encipher and decipher the message.

Asymmetric encryption

A cryptographic method that incorporates the mathematical operations involving both a public key and a private key to encipher or decipher a message. Either key can be used to encrypt a message, but then the other key i used to decrypt it.

Transposition cipher

A cryptographic operation that involves simply rearraging the values within a block based on an established pattern. AKA permutation Cipher

Vernam Cipher

A cryptographic technique developed at AT&T and known as the "One time pad" this cipher uses a set of charachters for encryption operations only one time then discards it.

Exclusive or Operation (XOR)

A function within boolean algera used as an encryption function in which two bits are compared. If the two bits are dentical the result is binary 0; otherwise the result is a binary 1.

Deffie hellman key exchange

A hybrid Cryptosystem that facilitates the exchanging private keys using public key encryption

Message authentication code (MAC)

A key dependent, one way hash function that allows only specific recipients (Symmetric key holders) to access the message digest/

Secret Key

A key that can be sued in symmetric encryption both to encipher and decipher the message

Secure Electronic Transactions (SET)

A protocol developed by credit card companies to protect against electronic payment fraud.

SSL-Secure Sockets layer

A security protocol developed by Netscape to use public key encryption to secure a channel over the internet.

Secure Hash Standard (SHS)

A standard issued by NIST that specifies secure algorithms, such as sha-1 for computing a condensed representation of a message or data file

Privacy-Enhanced Email

A standard proposed by the internet engineering task force that uses 3des symmetric key encryption and RSA for key exchanges and digital signatures

Poly-alphabetic Substitution

A substitution cipher that incorporates two or more alphabets in the encryption process

Message Digest

A value representing the application of a hash algorithm on a message that is transmitted with the message so it can be compared with the recipients locally calculated hash of the same message. if both hashes are identical after transmission, the message has arrived without modification. AKA hash value

Vignere Cipher

An advanced type of substitution cipher that uses a simple poly-alphabetic code

Secure HTTP (HTTPS)

An extended version of HTTP that provides for the encryption of protected web pages transmitted via the internet between a client and server

Public Key Infrastructure (PKI)

An integrated system of software, encryption methodologies, protocols, legal agreements, and third party services that enable users to communicate securely through the use of digital certificates

Digital Signatures

Encrypted Message components that can be mathematically proven as authentic

Encapsulating security payload (ESP) Protocol

In IPSEC, a protocol that provides secrecy for the contents of network communications as well as a system to system authentication of data integrity verification.

Transport Mode

In IPSEC, an encryption method in which only a packets ip data is encrypted the the ip headers themselves; this method allows intermediate nodes to read the source and destination address

Tunnel Mode

In IPSEC, an encryption method in which the entire IP packet is encrypted and inserted as the payload in another ip packet. this requires that other systems at the beginning and end of the tunnel to act as proxies to send and receive the encrypted packets and then transmit the packets to their ultimate destination.

Certificate Authority

In PKI, a third party that manages users' digital certificates/

Registration Authority

In PKI, a third party that operates under the trusted collaboration of the certificate authority and handles day-to-day certification functions.

session keys

Limited use symmetric keys for temporary communications during an online sessions

Hash functions

Mathematical algorithms that generate a message summary or digest (fingerprint) to confirm message identity and integrity

Hash Algorithm

Public functions that create a hash value, also known as a message digest, by converting variable length messages into a single fixed length value

Digital certificates

Public key container files that allow pki system components and end users to validate a public key and its owner

Secure Multipurpose internet mail extensions (s/mime)

Security protocol that builds on the encoding format of the multipurpose internet mail extensions protocol and uses digital signatures based on public key cryptosystems to secure email.

Digital Signature Standard (DSS)

The NIST standard for digital signature algorithm usage by federal information systems. DSS is based on a variant of the EIGamal signature scheme.

Advanced Encryption Standard (AES)

The current federal standard for the encryption of data, as specified by NIST. AES is based on the Rijndael algorithm, which was developed by vincent rijmen and joan daemen

Cyrtology

The field of science that encompasses cryptogoraphy and cryptanalysis

IP Security (IPSEC)

The primary and now dominant cyrptographic authentication and encryption product of the IETF's IP protocol security working group. a framework for security development within the TCP/IP family of protocol standards, IPSEC provides application support for all uses within TCP/IP, including VPN.

Stenography

The process of hiding messages; for example, hiding a message within the digital encoding of a picture or graphic so that it is almost impossible to detect that the hidden message even exists.

cryptography

The process of making and using codes to secure information

Cryptoanalysis

The process of obtaining the plaintext message from a ciphertext message without knowing the keys used to perform the encryption

nonrepudiation

The process of reversing public key encryption to verify that a message was sent by the sender and thus cannot be refuted.

Mono-alphabetic substitution

a substitution cipher that only incorporates a single alphabet in the encryption process

Substitution Cipher

an encryption method in which one value is substituted for another

Application Header (AH) Protocol

in IPSEC, a protocol that provides system to system authentication and data integrity verification, but does not provide secrecy for the content of a network communication

Certificate revocation list

in PKI, a published list of revoked or terminated digital certificates.

Pretty Good Privacy (PGP)

is a hybrid cryptosystem that combines some of the best available crytographic algorithms.