Cyphertext
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Cyphertext (alternatively, "ciphertext") is the output of an encryption operation, that is processing by a 'cypher' (alternatively, cipher, in which case we have 'ciphertext'). However spelled, it is different from codetext which is the output of processing plaintext using a code. Cyphertext will be seemingly random gibberish, which in fact contains the original message (the plaintext) in a form recoverable by those with the correct key. If the encrypted message is transmitted over some shared medium (eg, the Internet, in smoke signals or via drums) or an eavesdroppable medium (eg, the traditional telephone system), a third party can easily see that there is some data being transferred, and can most likely determine that it is encrypted. But if the cipher is secure, and uses an adequately chosen and cared for key, no eavesdropper is likely to learn much else about the plaintext. Traffic analysis of multiple such messages may, of course, provide other information.
Using steganography the cyphertext (more properly called stegotext as it need not be processed by a cypher) appears to be some harmless data, for example a photograph. The message is included in the image (eg, in the least significant bit of data for each pixel in the image) and is not obviously visible. Steganography is useful for hiding small amounts of plaintext in much larger collections of data.
See also