Dr. Dobb's Journal December 1998
The following notation is used throughout this paper.
Message Digest. Message digest hash functions produce a fixed-length output regardless of the size of the input. The probability of collision in the output space is very small.
Public Key Cryptography. Also known as "asymmetric encryption," this class of encryption algorithms requires that every user has a secret key and public key in his/her possession. The public keys are advertised, and anyone can retrieve them. If Alice wants to send a secret message to Bob, she encrypts the message using Bob's public key. Upon receiving the message, Bob can decrypt the message using his secret key. As only Bob knows his secret key, it will be difficult for an eavesdropper to decipher the message.
Digital Signature. To sign a message, Alice computes a one way hash function of the message, encrypts it with her secret key, and sends it with the plain text message. When Bob receives this message, he decrypts the signed message using Alice's public key, computes a hash output, and compares it to the plain text message. Any mismatch indicates that the plain text message has been tampered with.
Secret. A piece of information, such as a password, that is known only to one person or a limited number of people.
Nonce. A random number that occurs only once and is used only once.
-- T.A.