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VINSON
SAVILLE
SINCGARS
  
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KY-57   VINSON
Voice encryption unit - wanted item

TSEC/KY-57 is a wide-band secure voice (WBSV) encryption unit, developed in the mid-1970s by the US National Security Agency (NSA) as replacement for NESTOR cryptographic products like the KY-38. It was used with a wide range of military radios and over analogue telehone lines (POTS). As part of the VINSON family of devices, it was the main crypto workhorse of the US Army during the 1980s. Even today, many military radio sets and voice encryption units are still back­wards compatible with the KY-57. Also known by its National Stock Number NSN 5810-00-434-3644.

The KY-57 uses the GCHQ/NSA-developed Type-1 SAVILLE cryptographic algorithm. When used in combination with a radio transceiver, such as the SINCGARS non-ICOM RT-1439/VRC, the KY-57 allows signal fades or losses for up to 12 seconds without losing synchronization.

The KY-57 was eventually superceeded by the KY-99 that offers newer - more advanced - cryptographic algorithms, but that was still backward compatible with the KY-57. Later SINCGARS ICOM radios, such as the RT-1523, had built-in KY-57 (VINSON) compatibility.
  

KY-57 can encrypt both voice and data. Voice is digitized using Continuous Variable Slope Delta modulation (CVSD). 1 The output from the CVSD modulator is mixed with the output from the internal key generator, which is initialised with a so-called Traffic Encryption Key (TEK). The resulting 16 kbps data stream requires a 25 kHz wide-band radio channel, making it unsuitable for use on 3 kHz narrow-band HF radio frequencies. For this reason, KY-57 is VHF/UHF only. The device was first used in the early 1970s with the VRC-12.

The airborne version, with the same characteristics albeit in a different enclosure, is known as KY-58. The KY-57 was interoperable with the British BID/250 (Lamberton). It was sometimes used in combination with HAVE QUICK frequency hopping. Development of the KY-57 started in 1972, with the first devices being available in 1975. it was widely fielded in the early 1980s and was in production until 1993, when it was superceeded by more advanced encryption units such as the KY-99 and radios with integrated COMSEC [1], such as the modern SINCGARS radios.

Nevertheless, many KY-57 devices remained in use for several decades, which prompted the NSA in 2013 to start the VINSON/ANDVT Cryptographic Modernization program (VACM) [2]. In 2014, the development contract was awarded to Raytheon [3]. This resulted in the KY-57M and KY-58M drop-in replacements, that were in production until at least 2021 [4]. As they use the SAVILLE encryption algorithm, they are still deemed secure, more than 50 years after their inception.

  1. CVSD is also used in other voice encryption products of the same era, such as the Philips Spendex-10 , the Spendex 50 and the Telsy TS-500.

KY-57 left angle view
KY-57 right angle view
KY-57 front angle view
Front panel
Rear panel
Radio connector
Fill and Audio sockets
Tamper switch and notch in the top lid
Battery compartment
Wiping all keys (ZEROIZE ALL)
A
×
A
1 / 10
KY-57 left angle view
A
2 / 10
KY-57 right angle view
A
3 / 10
KY-57 front angle view
A
4 / 10
Front panel
A
5 / 10
Rear panel
A
6 / 10
Radio connector
A
7 / 10
Fill and Audio sockets
A
8 / 10
Tamper switch and notch in the top lid
A
9 / 10
Battery compartment
A
10 / 10
Wiping all keys (ZEROIZE ALL)

Features
All controls of the KY-57 are on the front panel. The three major connectors are on the front panel as well. The only other connector is the power socket which is located at the rear panel. A detailed description of all connectors can be found on Brooke Clarke's website. A detailed description of the U-229 AUDIO/FILL sockets can be found here.

Controls
  • S1 - Operation (right)
    OFF: Power OFF
    ON: Power ON
    TD: Power ON with Time Delay enabled (needed for satellite use)

  • S2 - MODE (center)
    P: Plain voice (pull out knob first)
    C: Crypto
    LD: Load keys manually
    RV: Remote key loading (Remote Variable, OTAR)

  • S3 - Key (left)
    Z 1-5: ZEROIZE keys 1 to 5 (pull out the knob first)
    1-5: Selection of the Traffic Encryption Key (TEK)
    6: Select the Key Encryption Key (KEK) for OTAR-use
    Z ALL: ZEROIZE ALL keys (pull out the knob first)

  • R1 - Volume
    This is an analog control (potentiometer) that is used for controlling the audio volume of the unit. Turn right to raise the volume.
Connections
  • J1 - AUDIO (right)
    Standard U-229 6-pin socket for the connection of audio equipment such as a headset and/or microphone.

  • J2 - FILL (center)
    Standard U-229 6-pin socket for the connection of a US military DS-102 compatible key fill device such as the KYK-13.

  • J3 - RAD (left)
    19-pin connection to a suitable radio set, such as the PRC-77 UHF FM rig.

  • J4 - POWER (rear)
    Standard US military power connector. Used for the connection of a battery box or an external power adapter.
Cryptographic Keys
The KY-57 has room for 6 front panel selectable cryptographic keys. Keys 1 to 5 are the Traffic Encryption Keys (TEK). They are either loaded manually, using a key fill device such as the KYK-13 and the KOI-18, or by means of Over The Air Rekeying (OTAR). Key number 6 must always be loaded manually as it is the Key Encryption Key (KEK) that is used for OTAR.

When loading the keys manually, the MODE selector (S2) should be placed in the LD-position. When updating keys 1 to 5 remotely, S2 should be set to RV (Remote Variable).

  


Parts
TSEC/KY-57 (VINSON) voice encryption unit
Bracket for vehicle mounting
HYP-57/TSEC power adapter box
Battery box
Wireline adapter HYX-57
Short radio cable
Power cable
Fill cable
Military handset H-250/U with U-229 connector (or equivalent)
Backup battery BA-5372 or equivalent
AN/KOI-18 Key Tape Reader
AN/KYK-13 Key Transfer Device
Terminal   KY-57
The central piece of a VINSON installation is the KY-57 terminal shown inthe image on the right. It can be used as a stand-alone device – with a battery connected at the rear – but also as part of a complete (secure) radio setup, in which case the radio is connected to the RADIO con­nec­tor at the bottom left of the front panel.   

Mounting bracket
The image on the right shows a typical mounting bracket that was used to mount the KY-57 inside a vehicle. The bracket is also suitable for devices that are housed in a similar case, such as the KY-99 and the HYX-57 wireline adapter.

  

Power adapter   HYP-57
The HYP-57 power adapter converts the 6-pin power connector of the KY-57 to the 5-pin power connector present in most vehicles.

This power adapter is also needed when the KY-57 is to be fitted in the MA-4626 cradle. A suitable power cable was supplied with the MA-4626 kit. The HYP-57 power adapter was latr resused with KY-99 — the successor of KY-57.

 Pinout of both connectors

  

Battery box
The battery box shown in the image on the right can be attached to the rear of the KY-57 and offers space for a standard 2 × 12V battery pack such as the BA-590, BA-5590 or equivalent.

These battery packs consists of two 12V batte­ries, both of which are wired individually to the 6-pin connector. This way the equipment can use them eiter in parallel (12V) or series (24V). In the KY-57 they are used in series (24V).

  

Wireline Adapter   HYX-57
The HYX-57 wireline adapter allowed two KY-57 units to be interconnected via a 2- or 4-wire telephone line, up to a distance of 16 km (10 miles). In case longer distances were required, multiple HYX-57 units could be cascaded.

 More information

  

Radio cable
A radio set can be connected to the RADIO connector on the front panel of the KY-57, by means of a suitable radio cable, such as the one shown in the image on the right. It has a 19-pin connector at the KY-57 end, and a connector for the radio set at the other end. In most cases this will be a 5- or 6-pin U-229.

The radio cable shown here is rather short, which means that the KY-57 had to be placed very close to the audio connector of the radio.
  

Power cable
The MA-4626 cradle comes with a short 2-wire cable with a 5-pin female connector, as shown in the image on the right. It is used to supply 24V to the KY-57 via the HYP-57.

The white wire (pin A) should be connected to a +24V/DC source, whilst the black wire (pin B) is used for the 0V (ground).

 Pinout of the power connector

  

Fill cable
When connecting a common FILL device — such as the KYK-13 — to the FILL port of the KY-99, a suitable FILL cable should be used, such as the one shown in the image on the right. Note that the cable shown here, has a pivoting connector at one end, making it easier to guide the cable.

This cable has a 6-pin U-229 connector at either end, and is wired straight-through (i.e. 1:1).

 Pinout of the U-229 connector

  

Handset   H-250/U
A regular mulitary handset with U-229 connec­tor, such as the H-250/U shown in the image on the right, should be connected to the AUDIO connector (AUD) at the front panel of the KY-57.

In most cases this will be the handset that was supplied with the radio set.

  

Backup battery   BA-5372
When the KY-57 is switched off, the crypto­graphic keys are retained in memory by means of a 6V backup battery that is installed behind a small panel at the bottom of the device.

In the past, a BA-590 battery was used, but this has since been superceeded by the BA-5590, which is available from several suppliers in the US. Users in other countries may have difficulty sourcing this battery, as it contains Lithium and is not allowed to be shipped by air mail.

 Datasheet

  

Key tape reader   KOI-18
Cryptographic keys must be loaded into the KY-57 by means of a DS-102 compatible key tape reader, such as the KOI-18 shown in the image on the right, or a key transfer device like the KYK-13 shown below.

The KOI-18 has the advantage that it can transfer key of unlimited length. It works by connecting the KOI-18 to the FILL socket of the KY-57 and pulling an 8-level punched paper tape through the reader. The key is not stored in the KOI-18 as it does not have a memory.

 More information

  

Key transfer device   KYK-13
In most cases, the KOI-18 tape reader shown above was used to load the cryptographic key into a key transfer device like the KYK-13 shown in the image on the right. The KYK-13 can hold up to 6 keys simultaneously, which can then be selected with a 6-position rotary switch at the front of the device.

The KYK-13 was then used to transfer the key(s) to one or more KY-57 devices in the field.

 More information

  

KY-57 left angle view
HYP-57 power adapter (front)
HYP-57 power adapter (rear)
Short radio cable for KY-57
Power cable
Power connector
Fill cable
Pivoting connector
H-250/U handset with coiled cable
H-250/U handset
BA-5372 backup battery
BA-5372 backup battery
KOI-18 with open lid
KYK-13 key transfer device
Mounting bracket
Bottom view
KY-57 with mounting bracket
KY-57 in mounting bracket
Cable
Cable
Cable
Cable
B
×
B
1 / 22
KY-57 left angle view
B
2 / 22
HYP-57 power adapter (front)
B
3 / 22
HYP-57 power adapter (rear)
B
4 / 22
Short radio cable for KY-57
B
5 / 22
Power cable
B
6 / 22
Power connector
B
7 / 22
Fill cable
B
8 / 22
Pivoting connector
B
9 / 22
H-250/U handset with coiled cable
B
10 / 22
H-250/U handset
B
11 / 22
BA-5372 backup battery
B
12 / 22
BA-5372 backup battery
B
13 / 22
KOI-18 with open lid
B
14 / 22
KYK-13 key transfer device
B
15 / 22
Mounting bracket
B
16 / 22
Bottom view
B
17 / 22
KY-57 with mounting bracket
B
18 / 22
KY-57 in mounting bracket
B
19 / 22
Cable
B
20 / 22
Cable
B
21 / 22
Cable
B
22 / 22
Cable

Demilitarized
Although the KY-57 is a relatively old device, it is still very difficult - if not impossible - to find a complete and working unit. This is mainly due to the fact that some KY-57 units might still be in operation with the US military or their Allies. Furthermore, later cryptographic devices, such as the KY-99 and some SINCGARS radios, are often backward compatible with the KY-57.


In the late 2000s however, demilitarized versions of the KY-57 sometimes showed up on auction sites such as Ebay. Although the internal electronics have all been removed from these devices, they are still cosmetically complete and do look nice in any cryptographic collection.

The image on the right shows an example of such a demilitarized KY-57 unit. All PCBs have been removed from their sockets and the flex wiring has been cut at various places. With some effort, it would be possible to convert the unit into a demonstrable dummy.

  


Connections
Audio
At the top left of the front panel of the KY-57 is a 6-pin U-229 connector (actually an U-283/U male panel mount) for connection of the audio accessories, such as a handset or headset. Below is the pinout of the AUDIO connector when looking into the receptacle.  More

  1. GND
    Ground
  2. SPK
    Speaker
  3. PTT
    Push-to-Talk
  4. MIC
    Microphone
  5. ?
  6. ?
FILL
To the left of the AUDIO connector is a 6-pin U-229 connector (actually an U-283/U male panel mount) for connection of a DS-102 FILL device, such as the KYK-13. Below is the pinout of the connector in FILL mode.  More

  1. GND
    Ground
  2. SWG
    Switched ground
  3. ACK
    Fill request acknowledgment
  4. DATA
    Fill data into KY-99
  5. CLK
    Fill clock into KY-99
  6. ?
KY-57 power
Below is the pinout of the power connector at the rear of the KY-57 when looking into the re­cep­tacle. The pin numbers are printed inside the receptacle. The device is suitable for connection of a BA-590 battery pack (or equivalent), which consists of two individually wired 12V batteries. As the KY-57 should be powered by 17 to 40V/DC, the receptacle is internally wired in such a way — pin 2 is connected to pin 4 — that the two 12V batteries are connected in series. When the device is used with an external 24V source, power should be applied to pins 1 (0V) and 5 (+24V).

  1. 0V (1)
    0V
  2. 0V (2)
  3. unused
  4. +12V (1)
  5. +12V (2)
    +24V
  6. unused
    Power connector at the rear of the KY-57 when looking into the male receptable.
HYP-57 Power
The HYP-57 adapber box is a simple device that converts the standard 5-pin 24V power wiring of a military vehicle to the 6-pin connector of the KY-57. Below is the The wiring of the 5-pin receptacle at the rear of the HYP-57, when looking into the receptacle.

  1. +24V
    White
  2. 0V
    Black
  3. unused
  4. +24V
    Not used in supplied cable
  5. unused
    Power connector at the rear of the HYP-57 adapter when looking into the male receptable.
Specifications
KY-57
KY-57M
  • Device
    Modernized version of KY-57
  • Purpose
    Drop-in replacement for KY-57
  • Model
    KY-57M
  • Years
    2014-2021
  • Country
    USA
  • NSN
    5810-01-617-4664
  • Manufacturer
    Raytheon
  • Predecessor
    KY-57
  • Successor
    KY-99, ANDVT
Documentation
  1. TM 11-5810-256-OP-2
    Technical Manual TSEC/KY-57

    Headqarters, Department of the Army, Washington, 1 December 1981. 1

  2. TB 11-5810-256-14
    Technical Bulletin TSEC/KY-57

    General maintenance information for COMSEC equipment TSEC/KY-57.
    Headqarters, Department of the Army, Washington, 4 March 1985.

  3. TM 11-5810-256-OP-6
    Operating Procedures KY-57
       WANTED

    Operating Procedures for Communications Security Equipment TSEC/KY-57
    (with HYX-57/TSEC) FM Secure Remote Communications.
    Headqarters, Department of the Army, Washington, 12 May 1983.

  4. TM 11-5820-890-10-1
    SINCGARS ICOM Ground Combat Net Radio

    Headqarters, Department of the Army, Washington, 1 September 1992. 2

  5. TM 11-5820-890-10-3
    SINCGARS NON-ICOM Ground Combat Net Radio

    Headqarters, Department of the Army, Washington, 1 September 1991. 2

  6. TB 11-5820-890-10-3
    Operation of Wireline Adapter Cable CX-13310/VRC

    Headqarters, Department of the Army, Washington, 1 April 1993. 2

  7. CSESD-14
    Communications Security Equipment System Document for TSEC/KY-57/58

    NSA, July 1984. Unclassified parts only. #CM303091/C.

  8. VINSON equipment test procedure
    Applicable to KY-57, HYX-57, HYP-57 and KY-58.
    NSA, date unknown. Unclassified parts only. #CM303091/E.
  1. Scanned by Google.
  2. Provided by Liberated Manuals.

References
  1. Jane's Military Communications, 2005-2006, KY-57
    p. 509. ISBN 0-710-2699-1.

  2. GovTribe, VINSON/ANDVT Cryptographic Modernization (VACM) Production
    24 April 2013.

  3. GovTribe, VACM Notice of Proposed Contract Action
    20 August 2014.

  4. John Keller, Raytheon to provide cyber security and
    cryptographic capability for secure voice communications

    Military+Aerospace Electronics, 20 December 2016.
Further information
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Crypto Museum. Created: Saturday 18 September 2010. Last changed: Tuesday, 30 April 2024 - 20:00 CET.
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