The TSEC/KY-68 DSVT, or Digital Subscriber Voice Terminal, is a US military ruggedized

Rugged computer

A rugged computer is a computer specifically designed to reliably operate in harsh usage environments and conditions, such as strong vibrations, extreme temperatures and wet or dusty conditions...

, full- or half-duplex telephone terminal with a built-in encryption

Encryption

In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...

/decryption module for secure

Key (cryptography)

In cryptography, a key is a piece of information that determines the functional output of a cryptographic algorithm or cipher. Without a key, the algorithm would produce no useful result. In encryption, a key specifies the particular transformation of plaintext into ciphertext, or vice versa...

 traffic. Converting voice to digital form, it can communicate voice or data at 16 or 32 kbit/s. The KY-68 can operate via civilian and military switches

Electronic switching system

In telecommunications, an electronic switching system is:* A telephone exchange based on the principles of time-division multiplexing of digitized analog signals. An electronic switching system digitizes analog signals from subscriber loops, and interconnects them by assigning the digitized...

 in either encrypted or un-encrypted mode, or point-to-point (encrypted mode only).

Although used primarily for secure communications, the KY-68 can operate with a Digital Non-secure Voice Terminal (DNVT) as its partner. A local switch provides the KY-68 user with a warning tone when initiating communication with a nonsecure terminal.

The KY-68 is keyed using an Electronic Transfer Device, typically either a 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....

 or AN/CYZ-10

AN/CYZ-10

The AN/CYZ-10 Data Transfer Device, often called a Filler, Crazy 10, ANCD or DTD, is a United States National Security Agency-developed, portable, hand-held fill device, for securely receiving, storing, and transferring data between compatible cryptographic and communications equipment...

.

An office version (KY-78) has the same interior electronics as the KY-68, but has an exterior casing composed of lighter materials. In other respects, it is identical.

The KY-68 and KY-78 are approved for use with SECRET-classified information, and despite the KY-78 being compromise

Compromise

To compromise is to make a deal where one person gives up part of his or her demand.In arguments, compromise is a concept of finding agreement through communication, through a mutual acceptance of terms—often involving variations from an original goal or desire.Extremism is often considered as...

d in the early 1990s, both versions remain in use.

External links

• Jerry Proc's page on the KY-68
• The Signal Leader's Guide — Field Manual 11-43