The KSV-21 Enhanced Crypto Card is a US National Security Agency

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...

-approved PC card

PC card

In computing, PC Card is the form factor of a peripheral interface designed for laptop computers. The PC Card standard was defined and developed by the Personal Computer Memory Card International Association which itself was created by a number of computer industry companies in the United States...

 that provides Type 1 encryption

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...

 functions and key

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...

 storage to the STE

Secure Terminal Equipment

Secure Terminal Equipment is the U.S. Government's current , encrypted telephone communications system for wired or "landline" communications. STE is designed to use ISDN telephone lines which offer higher speeds of up to 128k bits per second and are all digital...

 secure telephones and other devices.

The KSV-21 is built by Mykotronx as a tamper-resistant reprogrammable module and is backwards compatible with the KOV-14

KOV-14

The KOV-14 Fortezza Plus is a US National Security Agency-approved PC card which provides encryption functions and key storage to the Secure Terminal Equipment and other devices...

 Fortezza Plus card. It adds features including support for SCIP, Enhanced Firefly

Firefly (protocol)

Firefly is a U.S. National Security Agency public-key key exchange protocol, used in EKMS, the STU-III secure telephone, and several other U.S. cryptographic systems.-References:* RFC 2522* , USAREUR Pamphlet 380-40...

 and NSA's 21st century Key Management Initiative.