Skipjack tuna commercial tunas, and its population is considered sustainable against its current consumption. Its fishing is still controversial due to the methodology, with rod and reel or fishery options being promoted as ecologically preferable. Purse seine methods are considered unsustainable by some authorities due to excess bycatch, although bycatch is said to be much reduced if fish aggregation devices are not used. These considerations have led to the availability of canned skipjack marked with the fishing method used to catch it. Skipjack is considered to have "moderate" mercury contamination. As a result, pregnant women are advised against eating large quantities. In
Skipjack (cipher) for US government applications. Skipjack uses an 80-bit key to encrypt or decrypt 64-bit data blocks. It is an unbalanced Feistel network with 32 rounds. It was designed to be used in secured phones. 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. A claimed attack against the full