The Clipper Chip
The "Clipper Chip" is a general name for a proposal that originated in the George H.W. Bush administration and was strongly pushed by the Clinton administration to establish a federal encryption standard that includes a "back door" for law enforcement.
Although so far unsuccessful, Clipper is probably a good indicator of the feds' long-term agenda.
Clipper was actually comprised of several parts:
The Skipjack encryption algorithm, which is classified, formed the basis for the Clipper components.
The Escrowed Encryption Standard (EES) was intended to replace the widely used Digital Encryption Standard (DES). EES involves components using the Skipjack algorithm, with skeleton keys held by federal agencies. Law enforcement officials (with a warrant of course, trust us) could obtain the escrowed keys to decrypt any EES-encrypted data.
The Clipper chip itself implements EES for telephones.
The Capstone chip implements EES for computers.
The Tessera card is a PC card containing Capstone.
When the Clinton White House announced plans to implement EES, the online community reacted strongly. As a result, plans for Capstone and Tessera were put on hold. Although the administration initially said they never intended to ban other means of encryption, then-FBI director Louis Freeh later said he would seek such a ban if criminals didn't use EES (duh).
EES met strong online opposition, and several Congressman promised to block appropriations for EES. After the 1995 federal building bombing in Oklahoma City, opportunists seized the chance to rush through a prefab Counter-Terrorism Bill, which included funding for Clipper.
To try to rescue the sinking Clipper Chip, U.S. federal agencies proposed a variation called Commercial Key Escrow, in which private companies would hold the skeleton keys and provide them to police when presented with a warrant.