[5] Skipjack was proposed as the encryption algorithm in a US government-sponsored scheme of key escrow, and the cipher was provided for use in the Clipper chip, implemented in tamperproof hardware.
Skipjack is used only for encryption; the key escrow is achieved through the use of a separate mechanism known as the Law Enforcement Access Field (LEAF).
It was declassified on 24 June 1998, shortly after its basic design principle had been discovered independently by the public cryptography community.
[7][8]In March 2016, NIST published a draft of its cryptographic standard which no longer certifies Skipjack for US government applications.
Additionally, in the Half-Life 2 modification Dystopia, the "encryption" program used in cyberspace apparently uses both Skipjack and Blowfish algorithms.