The note added to the previous post referencing KGB spies using crochet to encrypt secret cold war messages was added for personal amusement being unaware that knitting and crochet have actually been used to encrypt secret messages. Atlas Obscura explores the story of Phyllis Latour Doyle, a secret agent during World War II who encrypted sensitive information in knitware for the British Secret Service. A precursor (or predictor?) to this story is the fictional steganographic tricoteuse Madame Defarge who appeared Charles Dickens’s Tale of Two Cities. Defarge used pattern stitches as a code to knit a list of names from the upper classes destined to face the guillotine. In his A History of Hand Knitting Richard Rutt explains:

Dickens was inspired by the “tricoteuses”, women who attended the National Convention in which the fate of the unfortunate rich was debated during the French revolution, knitting while they listened. Such a macabre pastime earned them a reputation as sadists, and an archetypal evil character was born in Madame Defarge. Dickens’was able to turn knitting, the frequent symbol of loving grandmothers and charming domesticity, into an ominous, cruel, inhuman act

The number of ways to encrypt text strings, or numerical data, into crochet is infinite but one way to start would be to look at simple cipher key-encoding systems and apply them to the process of interlocking loops of yarn. For example, Naomi Parkhurst at String Geekery, proposes converting letters into binary or Morse code and knitting secret messages in rows of noughts or dots (knits) and ones or dashes (purls).

But an encrypted message is only as secure as the key that was used to encrypt it. Given that modern highly secure keys use pseudo-random numbers to encode plaintext (human readable) into ciphertext (non-human readable) we could expect that more cryptically secure messages may create more random looking encrypted crochet (concealing any intelligible patterns that might give the game away). But the increase in randomness would also increase the probability of a series of consecutive knits or purls too large to sustain a physical structure. The most secure cryptograms might well be unknittable or create very fragile filigrees of fabric. But what would be more secure than a concealed message that literally just falls apart in the enemy’s hands without the (encrypted) knowledge of how to handle it to prevent its disintegration?

Other mathematical systems that have been used in cryptographic keys include prime numbers, cellular automatons and chaotic functions. Just how well crochet (essentially a binary system) can be seen as vehicle for mathematical information – further lending itself well to steganography – can be seen in the following few links:

Knitting Chaotic Attractors and Hyperbolic Surfaces.

Cellular Automaton Crochet – A lace Sierpinski triangle.

Cellular Automaton Pattern Generator (for knitting).

Cellular Automata Charts for Knitting.

Note: This post may well have been an excuse to post another set of anonymous, aesthetically cryptic crochet patterns, some of which resemble medieval cipher wheels and language mapping charts.