In cryptography, Crab is a block cipher created by Burt Kaliski and Matt Robshaw in 1993. Not really intended for use, Crab was developed to demonstrate how ideas from hash functions could be used to create a fast cipher. In cryptography, MD5 (Message-Digest algorithm 5) is a widely used cryptographic hash function with a 128-bit hash value. ... In cryptography, the key size (alternatively key length) is a measure of the number of possible keys which can be used in a cipher. ... In modern cryptography, symmetric key ciphers are generally divided into stream ciphers and block ciphers. ... The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κÏÏ ÏÏÏÏ kryptós hidden, and γÏάÏειν gráfein to write) is the study of message secrecy. ... Encryption Decryption In cryptography, a block cipher is a symmetric key cipher which operates on fixed-length groups of bits, termed blocks, with an unvarying transformation. ... In cryptography, a cryptographic hash function is a hash function with certain additional security properties to make it suitable for use as a primitive in various information security applications, such as authentication and message integrity. ...
Crab has an unusually large block size of 8192 bits. Its creators suggested using an 80-bit key, but the cipher could use any key size. The key is used to generate two large sets of subkeys: a permutation of the numbers 0 through 255, and an array of 2048 32-bit numbers. The block is divided into 256 32-bit subblocks, which are permuted at the beginning. Then the algorithm makes four passes over the data, each time applying one of four transformations adapted from MD5. In cryptography, the key size (alternatively key length) is a measure of the number of possible keys which can be used in a cipher. ... The key-schedule of DES In cryptography, the algorithm for computing the subkeys for each round in a product cipher from the encryption (or decryption) key is called the key schedule. ... In cryptography, MD5 (Message-Digest algorithm 5) is a widely used cryptographic hash function with a 128-bit hash value. ...
References
Schneier, Bruce. Applied Cryptography, 2nd edition, 1996. ISBN 0-471-11709-9.