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Electronic Transfer Device - Wanted item

The KYK-13 is a small electronic transfer device used by the military for the distribution of cryptographic material, commonly refererred to as Transmission Encryption Keys (TEK). It was developed by the US National Security Agency (NSA) and uses the DS-102 protocol for key transfer. The KYK-13 is also known by its National Stock Number NSN 5810-01-026-9618.

The KYK-13 was very popular because of its simplicity, small size and ease of use. A total of 6 TEK variables can be stored in the internal memory of the KYK-13, making it suitable for a variety of crypto devices, such as the KY-57 (Vinson), KY-99, some SINCGARS radios, KG-84, BID/250 (Lamberton) and even the latest KIV-7.

It was also used with the STU-II/B, KY-68, Spendex-40, Spendex-50 (DBT) and some other crypto phones. In normal use, the device itself is filled with cryptographic material from of a key management system (KMS) or another key filler.
KYK-13 key loader

The KYK-13 has 6 key compatments and supports a maximum length of 128 bits 1 for each key, making it suitable for a wide range of legacy crypto devices. It was first built in the 1980s and has been in service for over 30 years, with an excellent track record and wide user acceptance.

The KYK-13 was succeeded by a number of newer key fillers, such as the CYZ-10, the PYQ-10 and the Secure DTD2000 System (SDS), but they all missed the simplicity of the KYK-13. In 2009, the US Army announced the KIK-30 RASKL (Really Simple Key Loader) which is called the modern KYK-13 replacement by its manufacturer [2]. Despite that, the KYK-13 is still used widely today (2012). The only real drawback is that it only supports DS-102 and not the later DS-101 protocol.

  1. There has been some debate in the past as to the maximum length of the keys that can be stored inside the KYK-13. In some publications it is stated that it is only suitable for 90-bit keys and that later devices (e.g. the CYZ-10) had to be used for the modern 128-bit keys [1]. This can not be true however, as all crypto phones listed above use the 128-bit key based SAVILLE algorithm.

KYK-13 key loader KYK-13 front view KYK-13 top view 6.5V battery inside the KYK-13 KYK-13 installed on a KY-68 Close-up of the KYK-13 on a Spendex-40

The KYK-13 is very easy to operate and has only a few controls. There are two rotary switches (mode and address) with a recessed push button in between them (transfer). The device has two U-229 type connectors for connection to a crypto device: a male type (J1) and a female type (P1). These connectors are electrically identical and can also be used for cloning two KYK-13 devices.

At the right is the ON/OFF switch (MODE). At the left is the selector for the required crypto key compartment (1-6). The button at the center (Transfer) is used to initiate a transfer, although in most cases a transfer should be initiated from the destination device (e.g. a crypto phone). Any activity is indicated by the red LED. The unit is ZEROIZED (i.e. all keys destroyed) by setting the key compartment selector to Z ALL (ZEROIZE ALL) and turning the MODE switch to Z (ZEROIZE).

The KYK-13 is powered by a single internal 6.5V battery that is installed in a small compartment at the rear of the unit. A small aluminium panel with two screws gives access to the battery and allows it to be replaced within minutes. The image on the right shows the KYK-13 after the battery cover has been removed.

Initially, the KYK-13 was used with the Mercury-based BA-1372/U battery, which has now been superceeded by the better BA-5372/U Lithium Manganese Dioxide battery. This battery is still available today from a variety of sources.
6.5V battery inside the KYK-13

The design of the KYK-13 is similar to the MX-18290 Transmission Security Key Fill Device, featuring a similar case, similar controls and identical connectors. The KYK-13 however, is much smaller and can be used for cryptographic keys, whilst the MX-18290 is only suitable for transferring Frequency Hopping tables, also known as Transmission Security Keys (TSK).

The KYK-13 is used all over the world with a variety of devices, ranging from crypto phones and similar equipment, to frequency hopping radios (FH), airplane transponders (Identification Friend or Foe, or IFF) and GPS devices.

The KYK-13 can hold up to six keys (or key variables) in its memory, with a maximum of 128 bits for each key. Each key consists of 120 key bits (i.e. the actual key) and an 8-bit checksum. As there is no way to tell which key is used for what purpose, there are 6 writable fields on the side panel of the device, as shown in the image.
KYK-13 front view

The six white ovals in the image above are somewhat recessed and have a plastic background, so that they can be written with a pencil. As per convention, they would generally be used to indicate the type of key and the valid crypto period. For example, if compartment #1 contains a Secure Voice key that is valid until 24 February, oval #1 could read something like: SV 24 Feb.

KYK-13 with open battery compartment 6.5V battery inside the KYK-13 Typical 6-Volt BA-5372/U battery The KYK-13 in front of the MX-18290

In use
Although the KYK-13 can be connected to any DS-102 compatible device by means of a so-called fill cable, it is constructed in such a way that it can be fitted directly to the FILL connector of most crypto devices. As it has both a male-type and a female-type connector, one will always fit.


Just as an example, the KYK-13 is shown here on top of the KY-68 military crypto phone that was used in the US Army during the 1990s. It is connected directly to the FILL connector of the KY-68, and was used for transferring various types of keys.

 More about the KY-68
Using the KYK-13 on a KY-68 crypto phone
Spendex 40

The KYK-13 was also a popular device outside the US Army. The image on the right shows a KYK-13 unit connected to a Philips Spendex-40 military-grade crypto phone. It is used here to load the Traffic Encryption Keys (TEK) into the secure telephone.

 More about Spendex 40
Using the KYK-13 with the Spendex-40 crypto phone

Over the years, the KYK-13 has arguably become one of the most popular fill devices of all times, because of its small size, light weight and ease of use. In fact it was so popular that it was always in short supply. It has become the standard by which all later key fillers are referenced.

Using the KYK-13 on a KY-68 crypto phone KYK-13 installed on a KY-68 Using the KYK-13 with the Spendex-40 crypto phone Close-up of the KYK-13 on a Spendex-40

The KYK-13 is a powerful yet rather simple device. It could be serviced at the depot and can be opened by removing the four bolts at the corners of the front panel. After removing the front panel, the interior becomes visible, revealing the solder side of the main Printed Circuit Board.

The Printed Circuit Board (PCB) is held in place by four small cross-head bolts and contains a connector (at the other side) that slots directly into another PCB that contains the controls.

After removing the bolts, the PCB and easily be lifted off the lower PCB. The image on the rights shows the main PCB aside the KYK-13, with its component side facing upwards.

The double-sided PCB is relatively simple and contains only a handful of components. At the lower half is the black sockets for the lower PCB.
The main PCB removed from the KYK-13

The rest of the PCB contains only two critical components: the main controller (ON512432) and a static RAM memory chip (ON202178). Both chips are custom made (OEM) by Harris. The main controller is probably a custom-designed Application Specific Integrated Circuit or ASIC. Judging from the date codes on both chips, the device shown here was made in or around 1986.

KYK-13 front view KYK-13 interior Solder side of the KYK-13 PCB The main PCB removed from the KYK-13 Component side of the KYK-13 PCB Close-up of the custom-designed ASIC Custome-designed static memory (RAM) KYK-13 with open battery compartment

Please note that neither the KYK-13 nor its documentation is classified or otherwise restricted. Only when the device is loaded with a valid key, it becomes classified to the level of the key. KYK-13 is approved by the NSA for the distribution of Type-1 cryptographic keys.

Because of the success of the KYK-13 and its ever short supply, some manufacturers have produced functional clones of the devices. One example is the KSP-1 made by the German manufacturer ANT. It is fully compatible with the KYK-13 but has 32 key compartments.

Another example is the UP-2001, shown in the image on the right, made by Philips Usfa in The Netherlands in 1990. It resembles the KYK-13 but has 40 key compartments. Instead of the second U229 connector is has a 9-pin RS-232 socket for the connection of a barcode reader.
Philips UP-2001 key filler

Compatible equipment
The following encryption/decryption units are compatible with the KYK-13:

  1. Kathleen Hickey, DOD modernizes cryptographic device
    Defense Systems website, 12 November 2009. Retrieved May 2012.

  2. Sypris Electronics, RASKL KIK-30
    Retrieved May 2012.

  3. Enhanced Online News, Sypris Electronics Awarded Multi-Year $200 Million Contract...
    11 November 2009. Retrieved May 2012.
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