In 2005, a British rotor machine named Singlet (BID/60) S/N 13 was put on display at Bletchley Park in the Enigma and Friends exhibit assembled by David White and John Alexander. (Photo by Matt Russell)
The caption at Bletchley Park reads: "Singlet was used mainly by the British intelligence services from around to the 1949/50 to the early 1980's. This is a 'Cold War' machine using wired rotors to achieve secure messages. We are very grateful to the Foreign and Commonwealth Office and GCHQ for this opportunity to show `Singlet' here at BP."
Singlet has windows and stepping levers for ten rotors. The rotor tube appears to be a detachable section, labelled BID/60/3, while the base unit is labelled BID/60/1. There is a hint of a connection to the KL-7 in this naming of the major components .
The BID 60 major component are named as follows with their similarity to the KL7 in parenthesis.
Base unit AFSAM 7/1 (KLB),
Rotor stepping unit AFSAM 7/2 (KLA)
Rotor basket AFSAM 7/3 (KLK).
The rotor tube, stepping levers and the keyboard are also all somewhat suggestive of some sort of link or common ancestry with the KL-7. MIke Simpson confirms that the rotors were the same and BID60 could encipher/decipher Adonis traffic by simply using 8 instead of 10 rotors, thus making the machine suitable for use between it's major UK users and also with NATO members.
This view shows some of the lid details. (Photo by Magnus Manske)
Rotor basket closeup. (Photo by Matt Russell) Above, side view. (Photo by Matt Russell) Low front view. (Photo by Matt Russell)
The (UK) National Archives has a few scraps of information about the Singlet and its relationship with the KL-7 Adonis system. In the UK, the KL-7 was initially given the designator AFSAM 7. Most useful are files PRO HW 9/4 and PRO HW 9/5, which are minutes of meetings for the production of keying materials. Several of the documents imply that Adonis was introduced to replace the Combined Cypher Machine (CCM) in mid-1956, e.g.: "CS(R)2b said that it was now practically certain that Adonis would be introduced on the 1st July, 1956, in which case no further C.C.M. Key Lists would be required." (minute from early 1956).
In 1955, the committee noted the terminology change from AFSAM 7 to KL-7 : "Mr Chadwick confirmed that the title TSEC/KL7 should be used instead of AFSAM 7." Also in 1955, Singlet is described as similar to AFSAM 7, except that it used 10 rather than 8 rotors:"The Chairman said that there would be in due course a requirement for Key Lists for Singlet/Pendragon. This was similar to AFSAM 7 except that there were ten rotors instead of eight and therefore two further columns would be required. Mr Chadwick said that a long letter-check and a crossover setting might possibly be required."In January 1951, several future systems were discussed, including Singlet:"British "Singlet". No date had been fixed for the introduction of this device but it would not be ready before January, 1955. It would use 10 drums but the total from which these 10 would be selected was still undecided."And "BRUTUS":"Improved Combined Cypher Machine. Agreement of the British Chiefs of Staff and the American Chiefs of Staff had now been obtained for a combined cypher machine based on "BRUTUS". The introduction of "BRUTUS", which would have a selection of 7 out of 10 rotors and probably 6 movable tyres out of 20, was scheduled for January, 1955. In the meantime, an improved form of the present combined cypher machine was being prepared..."Supposing the Combined Cypher Machine was eventually replaced by the KL-7 in 1956 as implied earlier, perhaps BRUTUS was an early KL-7 prototype? (The KL-7 used 8 rotors, of course, 7 movable).
On the policy for replacing rotors (1957):(a) Replacement of Present Rotors for Adonis "CS(R)2b stated that the U.K. Services had been recommended to replace rotors not less frequently than every three years and it had been ascertained that this was also the policy of the U.S. Services. It was, therefore, probable that a similar policy would be adopted for the N.A.T.O. rotors ASMP 3001, in which case they would be replaced in 1959/60."Another file, PRO FCO 19/90, contains a document written to the British Defence Liaison Staff in Wellington, New Zealand, on the 19th June 1969:"The radiation characteristics of ROCKEX V and SINGLET are very different, those of the latter being markedly better. Nonetheless, SINGLET requires a secure perimeter of 50 feet and it is clear that this cannot be obtained in your present location."
|This photo features the rotors and the storage case. (Photo by Kevin Coleman)|
Credits and References:
2) Matt Russell <matt_crypto(at)yahoo.co.uk
3) Mike Simpson <ozbirds(at)optushome.com.au>
4) Kevin Coleman <k.coleman(at)ntlworld.com>