Glossary of Terms (Page 7)
S-HTTP - Secure HyperText Transfer Protocol, a secure way of transferring information over the World Wide Web.
S/MIME - Secure Multipurpose Internet Mail Extensions.
SSL - Secure Socket Layer. A protocol used for secure Internet communications.
salt - A string of random (or pseudorandom) bits concatenated with a key or password to foil precomputation attacks.
secret key - In secret-key cryptography, this is the single
key used both for encryption and decryption. Also called symmetric
key. DES is a secret key algorithm
secret sharing - Splitting a secret (e.g. a private key) into many pieces such that any specified subset of N pieces may be combined to form the secret.
secure channel - A communication medium safe from the threat of eavesdroppers.
seed - A typically random bit sequence used to generate another, usually longer pseudorandom bit sequence.
self-shrinking generator - A stream cipher where the output of an LFSR is allowed to feed back into itself.
self-synchronous - Referring to a stream cipher, when the keystream is dependent on the data and its encryption.
session key - A key for symmetric-key cryptosystems which is used for the duration of one message or communication session.
SET - Secure Electronic Transaction. MasterCard and Visa developed (with some help from the industry) this standard jointly to insure secure electronic transactions.
shared key - The secret key two (or more) users share in a symmetric-key cryptosystem.
shrinking generator - A stream cipher built around the interaction of the outputs of two LFSRs. See also stream cipher and linear feedback shift register.
Skipjack - The block cipher contained in the Clipper chip designed by the NSA.
SMPT - Simple Mail Transfer Protocol.
smartcard - A card, not much bigger than a credit card, that contains a computer chip and is used to store or process information.
special-purpose factoring algorithm - A factoring algorithm which is efficient or effective only for some numbers. See also factoring and prime factors.
standards - Conditions and protocols set forth to allow uniformity within communications and virtually all computer activity.
stream cipher - A secret-key encryption algorithm that operates on a bit at a time.
stream cipher based MAC - MAC that uses linear feedback shift registers (LFSR's) to reduce the size of the data it processes.
strong prime - A prime number with certain properties chosen to defend against specific factoring techniques.
sub key - A value generated during the key scheduling of the key used during a round in a block cipher.
S/WAN - Secure Wide Area Network
symmetric cipher - An encryption algorithm that uses the same key is used for encryption as decryption.
symmetric key - See secret key.
synchronous - A property of a stream cipher, stating that the keystream is generated independently of the plaintext and ciphertext.
tamper resistant - In cryptographic terms, this usually refers to a hardware device that is either impossible or extremely difficult to reverse engineer or extract information from.
TCSEC - Trusted Computer System Evaluation Criteria.
threshold cryptography - Splitting a secret (for example a private key into many pieces such that only certain subsets of the N pieces may be combined to form the secret.
timestamp - See digital timestamp
trap door one-way function - A one-way function that has an easy-to-compute inverse if you know certain secret information. This secret information is called the trap door.
trustees - A common term for escrow agents.
verification - The act of recognizing that a person or entity is who or what it claims to be.
Vernam cipher - See one-time pad.
weak key - A key giving a poor level in security, or causing regularities in encryption which can be used by cryptanalysts to break codes.
WWW - World Wide Web.
XOR - A binary bitwise operator yielding the result one if the two values are different and zero otherwise.
proofs - An interactive proof where the prover proves to the
verifier that he or she knows certain information without revealing