He's the guy who came up with the idea of using silk for codes, as silk won't be felt during pat-downs (paper will be felt). There's lots in the book of trying to work with local business who were obviously not willing to part with their valuable silk.
The book goes much more into details of transmitting these codes, the hassle of bruteforcing when somebody misremembered their code or mistranposed (there was an army of women working 24/7 trying out all possible codes). Highly suggested if the OP piqued your interest!
The seriousness of the topic really left a mark with me (thinking about agents being tortured and killed as a result of poor opsec or cryptographic vulnerabilities). I'm glad that the work I do doesn't have those consequences.
Although I have no specific complaint about this book, I actually didn't enjoy reading it as much as I had hoped, when it first came out. Leo Marks somehow just didn't make me want to read more, where Solly Zuckerman's book "from apes to warlords" which is about Operations Research and the bombing campaign in part totally did. Also R.V. Jones "most secret war" is a damn fine read.
If I remember it right, Leo Marks is the one who proved to the French their codes were completely bogus by breaking them, in front of their eyes with pen and paper. I bet they hated it, but it may have been highly beneficial it was irrefutable.
https://www.amazon.com.au/Between-Silk-Cyanide-Codemakers-19...
He's the guy who came up with the idea of using silk for codes, as silk won't be felt during pat-downs (paper will be felt). There's lots in the book of trying to work with local business who were obviously not willing to part with their valuable silk.
The book goes much more into details of transmitting these codes, the hassle of bruteforcing when somebody misremembered their code or mistranposed (there was an army of women working 24/7 trying out all possible codes). Highly suggested if the OP piqued your interest!