Cheetah is the hash function designed for the SHA-3 competition. Its name hints to its fast speed. Cheetah is the fastest among the AES-based hash functions.
Cheetah is based on AES, an elegant and widely used block cipher. However AES as it is can not be used as a compression function due to its small 128-bit block size and due to its relatively weak key-schedule, which was designed primarily for encryption.
Thus in Cheetah the AES round function was adapted in order to get a longer hash digest (256 or 512-bit) and a new message schedule was designed.
All the software tricks designed for speeding up AES can be used for Cheetah. Cheetah-256 has the speed equivalent to fastest AES-128 implementations, running at 9.3 cycles per byte and 15 cycles per byte on the 64-bit and the 32-bit reference platform respectively. Further optimizations might be possible.
Cheetah-512 runs at 13.6 cycles per byte and 15 cycles per byte on the 64-bit and the 32-bit, respectively.