Clefia (Paperback)

High Quality Content by WIKIPEDIA articles! CLEFIA is a new block cipher algorithm, developed by Sony. Its name is derived from the French word, clef, meaning key. The block size is 128 bits and the key size can be 128 bit, 192 bit or 256 bit. It is intended to be used in DRM systems. In cryptography, a block cipher is a symmetric key cipher operating on fixed-length groups of bits, called blocks, with an unvarying transformation. A block cipher encryption algorithm might take (for example) a 128-bit block of plaintext as input, and output a corresponding 128-bit block of ciphertext. The exact transformation is controlled using a second input - the secret key. Decryption is similar: the decryption algorithm takes, in this example, a 128-bit block of ciphertext together with the secret key, and yields the original 128-bit block of plaintext.