History of the Examination Unit

Set up during the Second World War and housed in the National Research Council, the Examination Unit (XU) was Canada's first cryptanalytic agency.

The XU was shut down in the closing days of the war, but elements of it were combined with related armed services SIGINT units to create the Joint Discrimination Unit, which evolved in 1946 into Canada's post-war SIGINT agency, the Communications Branch of the NRC (CBNRC), now known as the Communications Security Establishment. The XU was thus a direct ancestor of today's CSE.

A classified internal history of the XU was compiled under the editorship of Gilbert de B. Robinson, a Canadian mathematician who helped to establish the unit, worked on its staff, and served as its final director.

That 222-page document has long sat available in full to researchers on the shelves of Library and Archives Canada, but the only copy accessible on the Internet (through this blog) was a highly redacted version released more than 30 years ago through an Access to Information request. 

That sad state of affairs ends today. Here is the document in its entirety:

A History of the Examination Unit, 1941-1945 (61 MB PDF)

My thanks to the family of Examination Unit staff member David Hayne for sharing the hard copy with me.