Information Security CH 8
encapsulating security payload (ESP) protocol
In IPSec, a protocol that provides secrecy for the contents of network communications as well as system-to-system authentication and data integrity verification
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
registration authority (RA)
In PKI, a third party that operates under the trusted collaboration of the certificate authority and handles day-to-day certification functions.
exclusive OR operation (XOR)
a function within Boolean algebra used as an encryption function in which two bits are compared. If the two bits are identical, the result is a binary 0; otherwise, the result is a binary 1.
DIffie-Hellman key exchange
a hybrid cryptosystem that facilitates exchanging private keys using public-key encryption
secret key
a key that can be used in symmetric encryption both to encipher and decipher the message
message authentication code (MAC)
a key-dependent, one-way hash function that allows only specific recipients (symmetric key holders) to access the message digest
Secure Electronic Transactions (SET)
a protocol developed by credit card companies to protect against electronic payment fraud
Secure Multipurpose Internet Mail Extensions (S/MIME)
a security protocol that builds on the encoding formation of the MIME protocol and uses digital signatures based on public-key cryptosystems to secure e-mail
link encryption
a series of encryptions and decryptions between a number of systems, wherein each system in a network decrypts the message sent to it and then reencrypts the message using different keys and send it to the next neighbor
Secure Hash Standard (SHS)
a standard issued by the National Institute of Standards and Technology (NIST) that specifics secure algorithms, such as SHA-1, for computing a condensed representation of a message or data file.
Privacy-Enhanced Mail (PEM)
a standard proposed by the Internet Engineering Task Force (IETF) that uses 3DES symmetric key encryption and RSA for key exchange and digital signatures
polyalphabetic substitution
a substitution cipher that incorporates two or more alphabets in the encryption process
monoalphabetic substitution
a substitution cipher that only incorporates a single alphabet 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 recipient's locally calculated hash of the same message. If both hashes are identical after transmission, the message has arrived without modification.
transposition cipher
also known as a permutation cipher, an encryption method that involves simply rearranging the values within a block based on an established pattern to create the ciphertext
key
also known as cryptovariable, the information used in conjunction with an algorithm to create the ciphertext from plaintext or derive the plaintext from ciphertext
transport mode
an IPSec mode in which only the IP data is encrypted, not the IP headers
Vigenere cipher
an advanced type of substitution cipher that uses a simple polyalphabetic code
substitution cipher
an encryption method in which one value is substituted for another
cipher
an encryption method or process encompassing the algorithm, key and procedures used to perform encryption and decryption
asymmetric encryption
an encryption method that incorporates 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 is required to decrypt it.
symmetric encryption
an encryption method that incorporates mathematical operations involving the same secret key both to encipher and decipher the message
block cipher
an encryption method that involves converting plaintext into blocks or sets of bits and then converting the plaintext to ciphertext one block at a time
bit stream cipher
an encryption method that involves converting plaintext to ciphertext one bit at a time
Vernam cipher
an encryption process that generates a random substitution matrix between letters and numbers that is used only one time. Also called a one-time pad.
Secure HTTP (S-HTTP)
an extended version of Hypertext Transfer Protocol that provides for 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 enables users to communicate securely through the use of digital certificates
Internet Protocol Security (IPSec)
an open-source protocol framework for security development within the TCP/IP family of protocol standards
digital signatures
encrypted message components that can be mathematically proven as authentic
certificate revocation list (CRL)
in PKI, a published of revoked or terminated digital certificates
certificate authority (CA)
in PKI, a third party that manages users' digital certificates
Secure Sockets Layer (SSL)
A security protocol developed by Netscape to use public-key encryption to secure a channel over the internet
tunnel mode
An IPSec mode in which the entire IP packet is encrypted and then placed into the content portion of another IP packet
session keys
limited-use smmetric keys for temporary communications during an online session
hash functions
mathematical algorithms that generate a message summary or digest to confirm message identity and integrity
hash algorithms
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 identify its owner
digital signature standard (DSS)
the NIST standard for digial signature algorithm usage by federal information systems
work factor
the amount of effort required to perform cryptanalysis to decode an encrypted message when the key, the algorithm, or both are unknown
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.
ciphertext or cyptogram
the encoded message resulting from encryption
keyspace
the entire range of values that can be used to construct an individual key
steganography
the hiding of messages, within the digital encoding of a picture or graphic
plaintext
the original unencrypted message, or a message that has been successfully decrypted
code
the process of converting components of an unencrypted message into encrypted
cryptography
the process of making and using codes to secure the transmission of information
cryptanalysis
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
cryptology
the science of encryption, which encompasses cryptanalysis and cryptography
algorithm
the steps used to convert an unencrypted message into an encrypted sequence of bits that represent the messsage
decipher
to decrypt, decode, or convert ciphertext into the equivalent plaintext
encipher
to encrypt, encode, or convert plaintext into the equivalent ciphertext