Coding in which no information whatsoever is lost during the encoding (or decoding) process. Generally, encryption and decryption are lossless, as is channel coding. Strictly, data compaction is lossless, while data compression is not, but the latter term is often used for the former. The decoding of (i.e. recovery from) compression and compaction are lossless. But the decoding of a signal received from a channel is usually lossy (strictly not lossless) by design, since the noise at least must be lost: the message entering the channel will usually have been prepared so as to permit this loss by the use of an error-correcting code.