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Shabal function mode of operation. The chaining mode of Shabal works as follows: (A, B) ← PM,C (A, B, C) ← (A, C – M, B), (A ⊕ W, B + M), where M is the message block, and W is the counter. After processing all message blocks, three finalization rounds are applied in which the message block and the counter values are fixed.
Skein was created by Bruce Schneier, Niels Ferguson, Stefan Lucks, Doug Whiting, Mihir Bellare, Tadayoshi Kohno, Jon Callas and Jesse Walker.. Skein is based on the Threefish tweakable block cipher compressed using Unique Block Iteration (UBI) chaining mode, a variant of the Matyas–Meyer–Oseas hash mode, [3] while leveraging an optional low-overhead argument-system for flexibility.
The Merkle–Damgård hash function first applies an MD-compliant padding function to create an input whose size is a multiple of a fixed number (e.g. 512 or 1024) — this is because compression functions cannot handle inputs of arbitrary size. The hash function then breaks the result into blocks of fixed size, and processes them one at a time ...
The compression function can either be specially designed for hashing or be built from a block cipher. A hash function built with the Merkle–Damgård construction is as resistant to collisions as is its compression function; any collision for the full hash function can be traced back to a collision in the compression function.
The Whirlpool hash function is a Merkle–Damgård construction based on an AES-like block cipher W in Miyaguchi–Preneel mode. [2] The block cipher W consists of an 8×8 state matrix of bytes, for a total of 512 bits. The encryption process consists of updating the state with four round functions over 10 rounds.
OFB mode and CTR mode are block modes that turn a block cipher into a stream cipher. Cryptographic hash functions can be built using block ciphers. [47] [48] See the one-way compression function for descriptions of several such methods. The methods resemble the block cipher modes of operation usually used for encryption.
The following tables compare general and technical information for a number of cryptographic hash functions. See the individual functions' articles for further information. This article is not all-inclusive or necessarily up-to-date. An overview of hash function security/cryptanalysis can be found at hash function security summary.
The propagating cipher block chaining [25] or plaintext cipher-block chaining [26] mode was designed to cause small changes in the ciphertext to propagate indefinitely when decrypting, as well as when encrypting. In PCBC mode, each block of plaintext is XORed with both the previous plaintext block and the previous ciphertext block before being ...