Skipjack (cipher) - Cryptanalysis

Cryptanalysis

Eli Biham and Adi Shamir discovered an attack against 16 of the 32 rounds within one day of declassification, and (with Alex Biryukov) extended this to 31 of the 32 rounds (but with an attack only slightly faster than exhaustive search) within months using impossible differential cryptanalysis.

A truncated differential attack was also published against 28 rounds of Skipjack cipher. This was later complemented by a slide attack on all 32 rounds. Biham, Shamir and Biryukov's attack continues to be the best cryptanalysis of Skipjack known to the public.