Glossary of Terms (Page 7)
SHTTP  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 secretkey 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.
selfshrinking generator  A stream cipher where the output of an LFSR is allowed to feed back into itself.
selfsynchronous  Referring to a stream cipher, when the keystream is dependent on the data and its encryption.
session key  A key for symmetrickey 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 symmetrickey 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.
specialpurpose 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 secretkey 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 oneway function  A oneway function that has an easytocompute 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 onetime 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.
zero knowledge
proofs  An interactive proof where the prover proves to the
verifier that he or she knows certain information without revealing
the information.
