Government Code and Cypher School: Decrypts of Communist International (COMINTERN)...

HW 17

1930-1945

This series contains Communist International (COMINTERN) radio messages transmitted between Moscow and radio stations abroad decrypted by J H Tiltman and reported by GCHQ. Reports were classified most secret and were subsequently given the code name MASK.

The messages were encyphered with use of an encoded alphabet derived from a book held by both correspondents (usually a dictionary, but a telephone directory and other books were referred to in messages). Messages were transmitted between Moscow and clandestine radio stations in countries abroad. Some reports give the location of the radio station, while others give the station callsign. The correspondents abroad were agents or national Communist Party officials in Austria, China, Czechoslovakia, Denmark, France, Great Britain, Greece, Holland, Spain, Sweden, Switzerland and the United States. Messages covered a very wide variety of subjects ranging from policy, propaganda and publications to finance, demonstrations, training courses in the USSR, security, clandestine courier arrangements and issue of visas for travel to the USSR.

It should be noted the material released consists of typescript copies made in 1952-1953. The typing was not of the high standard required by GCCS and the many obvious errors would not have been permitted.

Reports are sorted alphabetically by country abroad from the USSR. Messages are given in chronological order. Message serial numbers apply to transmitted radio messages, usually quite short; a long message would be sent in several parts, thus the final report carried several numbers eg. 60: 61: 62. Separate serial number series were used for each channel of communication, but it should be noted that Moscow sometimes used more than one series to a particular correspondent. Correspondents, especially Moscow, were careless in their use of numbers, often re-using them for subsequent messages. Piece descriptions contain message serials listed by originator. It is clear that there were many gaps in interception often lasting for months at a time. The serial numbers of courier and visa messages issued in tabulated form interlock with the corresponding serial number ranges. The significance of the use in some reports of callsigns rather than place-names as originators or addressees is not known. This may have been an idiosyncrasy of an individual preparing reports. Generally serial number usage suggests that a callsign served the associated location.

In most cases, each month's-worth of messages has been catalogued as separate item. These items have been numbered arbitrarily for system reasons; the item numbers do not appear on the messages themselves.

Public Record(s)

English

81 file(s)

Open

In1997-2003 Government Communications Headquarters

Topics

Asia

Europe and Russia

Intelligence

Americas

Communications

Communism

Series is not accruing

All available material has been released to the Public Record Office. The whereabouts of the original reports has not been established.