Clipper Chip

Clipper Chip

In 1993, officials in the administration of President William Jefferson Clinton announced the proposed use of a cryptographic device intended to protect private communications for all but authorized monitoring by government agencies. Termed the "clipper chip," the device would permit secure encrypted voice communications, but would also allow United States law enforcement and intelligence agencies to monitor those communications by obtaining the algorithm keys to decrypt the transmissions.

As initially proposed the government would allow the keys to be maintained in a database held by an independent agent. Access to those keys would be permitted only as "legally authorized." Critics and privacy advocates immediately questioned the vague and broad use of the term legally authorized."

A chip similar in design and performance specifications, the Capstone chip, could be similarly regulated to allow secure data transmissions that could also be easily decrypted by United States law and intelligence agencies via known algorithmic keys.

An algorithm defines a repeatable step-by-step series of mathematical or language manipulation procedures to encrypt or decrypt a message or communication. Cryptology systems utilize algorithms and the labels, mechanics, recursive procedures, or other solutions are termed "keys" to the algorithm.

Use of the clipper chip was adopted and authorized in 1994. The National Institute of Standards and Technology (NIST) and the Department of the Treasury were designated to be the database repositories or "escrow" agents for the algorithmic keys. Rules regarding access to the keys were developed in accord with state and national security wiretap orders.

The clipper chip utilizes the SKIPJACK algorithm as part of the Escrowed Encryption Standard (EES) program. SKIPJACK was developed as a classified algorithm by the National Security Agency (NSA). SKIPJACk was initially developed as part of the Fortezza encryption suite and is a symmetric cipher with a fixed key length of 80 bits. Security experts assert that multiple encryption programs may eventually replace SKIPJACK like encryption-decryption programs.



Baker, Stewart A. "Don't Worry, Be Happy: Why Clipper Is Good for You." Wired. June 1994.

Johnson, George. "The Spies' Code and How It Broke," New York Times, Week in Review. July 16, 1995.


Cipher Key
Cipher Machines
Cryptology and Number Theory
Cryptology, History
NIST (United States National Institute of Standards and Technology)
NIST Computer Security Division, United States

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