The Escrowed Encryption Standard (EES) is a standard for encrypted communications that was approved by the U.S. Department of Commerce in 1994 and is better known by the name of an implementation called the Clipper chip. The significant feature of EES is its so-called key escrow method of enabling eavesdropping by authorized government agencies under certain circumstances.
The encryption/decryption algorithm used by EES is called SKIPJACK. The feature can be incorporated into communications devices including voice, facsimile (fax), and computer data. EES provides all the features of strong encryption with one exception: law-enforcement officials can intercept the communications given a court order allowing them to do so. This interception is made possible by means of a law-enforcement access field (LEAF), along with two decryption keys, one held by the National Institute of Standards and Technology (NIST) and the other held by Automated Systems Division of the Treasury Department.
The chip designed for implementing EES, and which was proposed by President Clinton for use in personal and business communications systems (including computers), was originally called Clipper. The initial public response was negative, presumably because people feared the use of the Clipper chip would become mandatory in all personal computers and other communications devices using strong encryption. There were also concerns about the possibility that the escrowed decryption keys could be obtained by unauthorized persons, or misused by overzealous government agencies.