Camellia

In cryptography, Camellia is a symmetric key block cipher with a block size of 128 bits and key sizes of 128, 192 and 256 bits. It was jointly developed by Mitsubishi Electric and NTT of Japan. The cipher has been approved for use by the ISO/IEC, the European Union's NESSIE project and the Japanese CRYPTREC project. The cipher has security levels and processing abilities comparable to the Advanced Encryption Standard. The cipher was designed to be suitable for both software and hardware implementations, from low-cost smart cards to high-speed network systems. It is part of the Transport Layer Security (TLS) cryptographic protocol designed to provide communications security over a computer network such as the Internet. The cipher was named for the flower Camellia japonica, which is known for being long-lived as well as because the cipher was developed in Japan. Design Camellia is a Feistel cipher with either 18 rounds (when using 128-bit keys) or 24 rounds (when using 192- or 256-bit keys). Every six rounds, a logical transformation layer is applied: the so-called "FL-function" or its inverse. Camellia uses four 8×8-bit S-boxes with input and output affine transformations and logical operations. The cipher also uses input and output key whitening. The diffusion layer uses a linear transformation based on a matrix with a branch number of 5.