[RINGS] Code/cipher definition

If there is any one here like me then this may be of some help. Code has a definition, which may help in the methods we use to make sense of the sequence.
Obviously those of you with masters in Crypto won't need this

CIPHERTEXT
The encrypted form of the PLAINTEXT.

CODE
An unvarying rule for replacing a piece of information with another object, not necessarily of the same sort e.g. ASCII.

CRYPTANALYSIS
The science (and art) of recovering information from ciphers without knowledge of the key.

CRYPTOGRAPHY
The science of the enciphering and deciphering of messages in secret code or cipher.

CRYPTOSYSTEM
A system for encrypting information.

DECRYPTION
The process of converting the CIPHER back into PLAINTEXT.

ENCRYPTION
The process of converting the PLAINTEXT into a CIPHER.

KEY
The secret information known only to the transmitter and the receiver which is used to secure the PLAINTEXT.

MONOALPHABETIC SUBSTITUTION
A method of encryption where a letter in the plaintext is always replaced by the same letter in the ciphertext.

PLAINTEXT
The source information to be secured.

POLYALPHABETIC SUBSTITUTION
A method of encryption where a letter in the plaintext is not always replaced by the same letter in the ciphertext.

[edit on 19-6-2004 by Smudge]

Just a small addition. Cipher is officialy the same as ciphertext, but it is sometimes also used to refer to the encryption process.