Really interesting analysis of the American M-209 encryption device and its security. [...]

The NSA’s “ National Cryptographic School Television Catalogue ” from 1991 lists about 600 COMSEC and SIGINT training videos. There are a bunch explaining the operations of various cryptographic equipment, and a few code words I have never heard of before. [...]

Really interesting article on the ancient-manuscript scholars who are applying their techniques to the Voynich Manuscript. No one has been able to understand the writing yet, but there are some new understandings: Davis presented her findings at the medieval-studies conference and published them in 2020 in the journal Manuscript …

Interesting paper about a German cryptanalysis machine that helped break the US M-209 mechanical ciphering machine. The paper contains a good description of how the M-209 works. [...]

The Polish Embassy has posted a series of short interview segments with Marian Rejewski, the first person to crack the Enigma. Details from his biography. [...]

During the Cold War, the US Navy tried to make a secret code out of whale song. The basic plan was to develop coded messages from recordings of whales, dolphins, sea lions, and seals. The submarine would broadcast the noises and a computer—the Combo Signal Recognizer (CSR)—would …

Through a 2010 FOIA request (yes, it took that long), we have copies of the NSA’s KRYPTOS Society Newsletter, “ Tales of the Krypt,” from 1994 to 2003. There are many interesting things in the 800 pages of newsletter. There are many redactions. And a 1994 review of Applied …

David Kahn has died. His groundbreaking book, The Codebreakers was the first serious book I read about codebreaking, and one of the primary reasons I entered this field. He will be missed. [...]

GCHQ has released new images of the WWII Colossus code-breaking computer, celebrating the machine’s eightieth anniversary (birthday?). News article. [...]