block cipher


block cipher

[′bläk ‚sī·fər] (communications) A cipher that transforms a string of input bits of fixed length into a string of output bits of fixed length.

block cipher

An encryption method that processes the input stream as groups of bytes that are fixed in size, typically 64, 128 or 256 bits long. The state of a block cipher is reset before processing each block. The DES and AES algorithms are examples of block ciphers (see DES and AES). Contrast with stream cipher.