authoritative definition of cryptography?

[peter honeyman]

according to denning's book, "cryptography is the science and study of 
secret writing."  webster's 7th says cryptography is "the enciphering 
and deciphering of messages in secret code."  kahn says "the methods of
cryptography ... render [a secret message] unintelligible to outsiders 
by various transformations of the plaintext."

	peter