The KYK-13 Electronic Transfer Device is a common 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....

 designed by the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 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...

 for the transfer and loading of cryptographic keys

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...

 with their corresponding check word.

Even though the KYK-13 is several decades old and was supposed to have been obsoleted by the AN/CYZ-10 Data Transfer Device

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...

, it is still widely used because of its simplicity and reliability.

It is battery powered and uses the DS-102 protocol for key transfer.

Its National Stock Number is 5810-01-026-9618.

Components

• P1 and J1 Connectors - Electrically the same connection. Used to connect to a fill cable, COMSEC device, KOI-18, KYX-15, another KYK-13, or AN/CYZ-10.
• Battery Compartment - Holds battery which powers KYK-13.
• Mode Switch - Three position rotary switch used to select operation modes.
  • "Z" - Used to zeroize selected keys.
  • ON - Used to fill and transfer keys.
  • OFF CHECK - Used to conduct parity checks.
• Parity Lamp - Blinks when parity is checked or fill is transferred.
• Initiate Push button - Push this button when loading or zeroizing the KYK-13.
• Address Select Switch - Seven position rotary switch.
  • "Z" ALL - Zeroizes all 6 storage registers when mode switch is set to "Z".
  • 1 THROUGH 6 - Six storage registers for storing keys in KYK-13.