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Tiger is a cryptographic hash function designed byRoss Anderson and Eli Biham in 1995 forefficiency on 64-bit platforms. The size of a Tiger hash value is 192 bits. Truncated versions(known as Tiger/128 and Tiger/160) can be used for compatibility with protocols assuming a particular hash size.Unlike the SHA-2 family, no distinguishing initialization values are defined; theyare simply prefixes of the full Tiger/192 hash value.
Tiger is designed using the nearly universal Merkle-Damgård paradigmThe one-way compression function operates on 64-bit words, maintaining 3words of state and processing 8 words of data. There are 24 rounds, using a combination of operation mixing with XORand addition/subtraction, rotates, and S-box lookups, and a fairly intricate key schedulingalgorithm for deriving 24 round keys from the 8 input words.
Although fast in software, Tiger's large S-boxes (4 S-boxes, each with 256 64-bit entries totals8 KiB) make implementations in hardware or smallmicrocontrollers difficult.