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The Medium is the Message: Textiles & Code-Breaking

Letters & Essays

The Medium is the Message: Textiles & Code-Breaking

By Julia Berick
Research by Autumn Hrubý & Julia Berick

The full essay will appear in
Hesperios Journal No. 4: Transport


Read the word “spy,” and you might vaguely picture a le Carré-ish bureaucrat. Add the word “cypher” to this picture, and he suddenly has a piece a chalk in his hand and a blackboard before him covered in code. The reality of cryptology and its challenges is, however, much more interesting. Not only does contemporary intelligence have less human focus on code-breaking, but the breaking of the code itself requires only a fraction of the effort. That said, no small amount of effort must still be made in covering the method of detection, or else the sender realizes the code has been broken, and the process must begin all over again.

One famous spy for the British during World War Two, Phyllis Latour Doyle, was chosen for her mission after several male colleagues had failed. (Unfamiliar men were, perhaps, more conspicuous in occupied France, and her predecessors were all detected and executed.) Latour Doyle parachuted behind enemy lines in Normandy and took up a French identity and established a French life, all the time sending coded messages to the allies about German troop location. She transmitted her messages by wireless, using one of the 2000 codes she kept on a piece of silk. The silk she wrapped around a knitting needle, slipped this into a shoelace, and used the whole apparatus to pin up her hair.

Other female spies likewise concealed code by using the ubiquitous wartime occupation of knitting, though most reports suggest that purls and stitches didn’t so much hold code as serve as a useful cover for a woman lingering on a bus or carrying a deep bag. Even so, there are, however, some instances of code within the weave.

The Belgian resistance relied on women knitting from train stations to record enemy maneuvers. These women used specific stiches to convey train movement. A dropped stitch, for example—usually an error in knitting—was used to create a small but meaningful hole in the fabric. Conveying messages through textiles had several major advantages. Unlike code transmitted by radio, the transmitter couldn’t be tracked, and in concealing messages in everyday objects, and by making use of their basic function, detection of the code bearer was furiously difficult.