Ciphertext - technical definition

A protected form of data. To transform a piece of plaintext into ciphertext, or to transform ciphertext into plaintext, an individual needs both an algorithm and a key. Keys are variable parameters of the algorithm. Whereas algorithms are widely distributed and public, the keys are limited to just a few individuals because knowing the key gives someone access to the data encrypted with that key.

The key’s size is an indication of its strength. It is an indication of the difficulty a cracker would have in ascertaining the plaintext from the ciphertext without knowing the particulars of the key. This difficulty, based on the size of the key, is known as the “work factor.”

See Also: Algorithm; Cryptography or “Crypto”; Key; Plaintext.