Key Escrow and Key Recovery
Law enforcement has always been concerned about the potential use of encryption for criminal purposes. To counter this threat, NIST published the Escrowed Encryption Standard (EES) in Federal Information Processing Standards (FIPS) Publication 185 (1994). The premise of the EES is to divide a secret key into two parts and place those two parts into escrow with two separate, trusted organizations. With a court order, the two parts can be obtained by law enforcement officials, the secret key recovered, and the suspected communications decrypted. One implementation of the EES is the Clipper Chip proposed by the U.S. government. The Clipper Chip uses the Skipjack Secret Key algorithm for encryption and an 80-bit secret key.