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HORA   BID/950
Digital On-Line Cryptographic Equipment - under construction

BID/950 was a medium speed teleprinter and data encryptor/decryptor, developed by Plessey in Liverpool (UK) in 1988 as part of the Cryptographic Equipment Low-speed Telegraph project (CELT) to replace the TSEC/KW-7 and the BID/610. In 1992 it was accepted by NATO [1] as a replacement for the BID/1000. BID/950 is also known as Digital On-Line Cryptographic Equipment number 2 (DOLCE II), by its codename HORA and by its NSN: 5810-99-256-0467.

The device was suitable for the encryption of teleprinter signals in the ITA2 standard (Murray) and data in the ITA5 standard (ASCII), at speeds ranging from 50 bps to 48,000 bps in 16 steps.

The image on the right shows a typical BID/950 device. All controls are at the front panel and all connections are at the rear, except for the U229 socket for the FILL Gun, which is located at the far right of the front panel. The large mechanical appendix at the center is an 8-level tape reader that could be used for loading key variables as an alternative to using a fill gun (e.g. KYK-13).
BID/950 (HORA) cipher machine

The BID/950 was considered a small device at the time. It is fitted in a standard 19" rackmount case and has a height of 2U (approx. 87 mm). In telegraphic mode (ITA2) is was the functional equivalent of two BID/610 units, however it was not interoperable with BID/610 equipment. In data mode it was interoperable with the BID/880. The machine could be used in CTAK and KAK mode, and could be clocked by an external device, such as a modem, up to 48,000 baud [2].

One manufacturer [3] claims they have a BID/950 application that allows data transfer rates of 64 kb/s and that two BID/950 units could be operated in parallel, in order to achieve a transfer rate of 128 kb/s (i.e. 2 x 64 kb/s). Apparently this was used within NATO for video conferencing. In most situations however, BID/950 was for teleprinter networks at the lowest speed of 50 baud.


BID   British Inter Departmental
Identification used for equipment used by the British Armed Forces and various Government departments. BID is sometimes erroneously explained as British Industrial Development (even by people in the know). Each device is identified by the abbreviation 'BID' followed by a '/' and a number, e.g. BID/950.
CFB   Cipher Feedback
A block cipher mode that enhanced ECB mode by chaining together blocks of cipher text it produces, and operating on plaintext segments of variable length, less than or equal to the block length.
CTAK   Cipher Text Auto-Key
Cryptographic logic that uses previous cipher text to generate a key stream. (Depricated terminology, superceeded by CFB)
KAK   Key-auto-key
Cryptographic logic using a previous key to produce a key. (Depricated terminology, superceeded by OFB)
OFB   Output feedback
a block cipher mode that modifies ECB mode to operate on plaintext segments of variable length lesss than or equal to the block length.
  1. NATO IACD Information Assurance, BID 950
    Retrieved March 2014.

  2. Jerry Proc, BID/950
    Retrieved March 2014.

  3. Scotty Group, Applications → Secure Communication Over Encryption Channels
    Website. Retrieved January 2015.
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Crypto Museum. Created: Tuesday 25 March 2014. Last changed: Sunday, 25 February 2018 - 13:49 CET.
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