High Quality Content by WIKIPEDIA articles! In cryptography, SWIFFT is a collection of provably secure hash functions. It is based on the concept of the Fast Fourier Transform (FFT). SWIFFT is not the first hash function based on FFT, but it sets itself apart by providing a mathematical proof of its security. It also uses the LLL basis reduction algorithm. It can be shown that finding collisions in SWIFFT is as least as difficult as finding short vectors in cyclic/ideal lattices in the worst case. By giving a security reduction to the worst case scenario of a difficult mathematical problem SWIFFT gives a much stronger security guarantee than most other cryptographic hash functions.