SAVILLE is an NSA

National Security Agency

The National Security Agency/Central Security Service is a cryptologic intelligence agency of the United States Department of Defense responsible for the collection and analysis of foreign communications and foreign signals intelligence, as well as protecting U.S...

 Type 1

Type 1 encryption

In cryptography, a Type 1 product is a device or system certified by the National Security Agency for use in cryptographically securing classified U.S...

 encryption algorithm

Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

. It is used broadly, often for voice encryption, and implemented in a large number of encryption devices.

Little is known publicly about the algorithm itself. Some documentation related to the KYK-13

KYK-13

The KYK-13 Electronic Transfer Device is a common fill device designed by the United States National Security Agency for the transfer and loading of cryptographic keys with their corresponding check word....

 fill device

Fill device

A fill device is an electronic module used to load cryptographic keys into electronic encryption machines. Fill devices are usually hand held and battery operated....

 and statements made by military officials suggest that SAVILLE has a 128-bit key. On the AIM microchip

Microprocessor

A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...

, it runs at 4% of the clock rate (compare DES

Data Encryption Standard

The Data Encryption Standard is a block cipher that uses shared secret encryption. It was selected by the National Bureau of Standards as an official Federal Information Processing Standard for the United States in 1976 and which has subsequently enjoyed widespread use internationally. It is...

 at 76% and BATON

BATON

BATON is a Type 1 block cipher in use since at least 1995 by the United States government to secure classified information.While the BATON algorithm itself is secret, the public PKCS#11 standard includes some general information about how it is used. It has a 320-bit key and uses a 128-bit block...

 at 129%). The Cypris chip

Cypris (microchip)

CYPRIS was a cryptographic module developed by the Lockheed Martin Advanced Technology Laboratories. The device was designed to implement NSA encryption algorithms and had a similar intent to the AIM and Sierra crypto modules...

 mentions 2 modes; specifications for Windster and Indictor specify that they provide Saville I.

Some devices and protocols that implement SAVILLE:

• The VINSON
  VINSON
  VINSON is a family of voice encryption devices used by U.S. and allied military and law enforcement, based on the SAVILLE encryption algorithm and 16 kbit/s CVSD audio compression. It replaces the Vietnam War-era NESTOR family....
  
   family (voice encryption)
• APCO Project 25 (single-channel land mobile radios) (Saville has algorithm ID 04)
• Versatile encryption chips: AIM, Cypris
  Cypris (microchip)
  CYPRIS was a cryptographic module developed by the Lockheed Martin Advanced Technology Laboratories. The device was designed to implement NSA encryption algorithms and had a similar intent to the AIM and Sierra crypto modules...
  
  , Sierra I/II, Windster, Indictor, Presidio, Railman