< cryptography > The practise and study of encryption and decryption - encoding data so that it can only be decoded by specific individuals. A system for encrypting and decrypting data is a cryptosystem. These usually involve an algorithm for combining the original data (" plaintext ") with one or more "keys" - numbers or strings of characters known only to the sender and/or recipient. The resulting output is known as " ciphertext ".
The security of a cryptosystem usually depends on the secrecy of (some of) the keys rather than with the supposed secrecy of the algorithm . A strong cryptosystem has a large range of possible keys so that it is not possible to just try all possible keys (a " brute force " approach). A strong cryptosystem will produce ciphertext which appears random to all standard statistical tests. A strong cryptosystem will resist all known previous methods for breaking codes (" cryptanalysis ").
See also cryptology , public-key encryption , RSA .
Usenet newsgroups: news:sci.crypt , news:sci.crypt.research .
FAQ MIT .
Cryptography glossary .
RSA cryptography glossary .
Cryptography, PGP, and Your Privacy .
(2000-01-16)