The 1944 Bletchley Park Cryptographic Dictionary

- 19 -

COLLECTIVE :

A general broadcast to all meteorological centres in a large area, (e.g. Europe) of all the synoptic weather observations made in that area at a particular (synoptic) hour.

COLOSSUS :

(in Tunny). One of the high-speed machines designed to set known chi wheels but also utilized for the determination of unknown chi- wheel patterns by Tutte's method, incorporating the five chi-wheel periods in the form of double rings of thyratrons controlled by the sprocket-holes in the teleprintor tape, reading tapes of cipher messages by photo-electric means, combining and differencing as required, counting by valve-counters, and finally delivering the results in typed form.

COLOUR :

(in Enigma). A key (keys having originally been given the names of colours).

COLUMN :

1. (in transposition ciphers). Any one of the "vertical" series of letters (under a number of the key) according to which the text is "taken out" of the cage in the process of enciphering or "written in" in the process of deciphering.

2. (in a Vigenere or similar table). Any one of the "vertical" series of letters or other symbols representing the sums, or differences, of the clear letters in the margin and the key-letter at the top, or indicating how the clear letters in the margin are substituted for a particular key-letter.

3. (in reciphered codes). A series of cipher-groups, usually one from each of a number of messages, which have been reciphered with the same subtactor group and so form a vertical series when the messages are written out in depth; also, a vertical series of groups on a subtractor sheet, etc.

4. (in machine and other substitution ciphers). A series of cipher letters or other symbols from the same or different messages which have been enciphered with the same key-letter or the same cipher alphabet and so from a "vertical" series when the messages are written out in depth or (in the case of periodic substitution) when the message or messages are written out on the width corresponding to the period.

COLUMN HEAD :

(in transposition ciphers). The letter or other symbol forming the top or head of a "column".

COLUMNAR :

(of transposition systems). Using "columns" as the basis of rearrangement.

| previous page | next page | index page |