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Embeddable COMSEC module - this page is a stub

RAILMAN is a low-speed full-duplex and half-duplex embeddable COMSEC module, in the form of a custom-specific integrated circuit (ASIC). It is used to secure digital voice and/or low-speed data traffic. The module is suitable for data traffic up to 500 Kb/s. It contains several (secret) encryption algorithms — including SAVILLE — and is approved by NSA for TOP SECRET traffic.

RAILMAN is a fully self-contained cryptographic processor, available in a 121-contact Pin Grid Array (PGA) package. The only external require­ment is an off-the shelf (volatile) static RAM chip for storage of the crypto variables. The device is known by the designator U-AXM, or by the De­partment of Defense part number ON452600-2.

The image on the right shows a U-AXM crypto processor (i.e. RAILMAN). The one shown here was manufacturered in week 12 of 1996 and was found on the E-HWX board of the KY-99 voice encryptor. It is the only secret part of the KY-99.

When unkeyed, RAILMAN is an unclassified Controlled Cryptographic Item (CCI). When keyed, it assumes the classification of the loaded key. It is cryptographically interoperable with VINSON, ANDVT, KG-84, WINDSTER and STU-III. It has been embedded in KY-99 (MINTERM), KY-100 (AIRTERM), SINCGARS ICOM/SIP radios 1 and the Unit level Circuit Switch (ULCS) [1].

The exact development date of the RAILMAN cryptoprocessor is currently unknown, but given the fact that it was men­tioned in the original specification of the CYPRIS cryptoprocessor (1992), it must have been available in 1992. We therefore assume that RAILMAN was developed in 1991. This is corroberated by the fact that service engineers were trained on the repair of the KY-99 voice encryption device — in which RAILMAN is present — as early as July/August 1992 [2].

  1. First used in 1996 in the SINCGARS RT-1523C (SIP) radio.

Equipment with RAILMAN on this website
KY-99 (MINTERM) Narrow-band Voice and Data Terminal
  • Device
    Cryptographic processor (module)
  • Purpose
    Embeddable in encryption device
  • Codename
  • Designator
  • Part number
  • Year
  • Country
  • Manufacturer
  • Algorithm
  • Package
    121 PGA
  1. RAILMAN standard embeddable module (U-AXM)
    Granite Island Group, 2002.

  2. Tim Weichel, Experience
    Certificate of the MINTERM full maintenance course. July-August 1992.
    Retrieved November 2009 from
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Crypto Museum. Created: Sunday 12 May 2024. Last changed: Tuesday, 14 May 2024 - 22:39 CET.
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