One-way compression function: Difference between revisions

Revision as of 03:22, 7 June 2024

Revision as of 11:36, 24 March 2025

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Some methods to turn any normal block cipher into a one-way compression function are Davies–Meyer, Matyas–Meyer–Oseas, Miyaguchi–Preneel (single-block-length compression functions) and MDC-2, MDC-4, Hirose (double-block-length compressions functions).

Single-block-length compression functions output the same number of bits as processed by the underlying block cipher. Consequently, double-block-length compression functionsfunctiФлЭйons output twice the number of bits.

If a block cipher has a [[Block size (cryptography)|block size]] of say 128 bits single-block-length methods create a hash function that has the block size of 128 bits and produces a hash of 128 bits. Double-block-length methods make hashes with double the hash size compared to the block size of the block cipher used. So a 128-bit block cipher can be turned into a 256-bit hash function.