[Cryptography] Leo Marks' 1998 talk about WW2 SOE code-making and breaking

[Steven M. Bellovin]

On 21 Jan 2026, at 12:58, Kent Borg wrote:

> On 1/21/26 9:14 AM, Steven M. Bellovin wrote:
>
>> I don't recall OTPs being used by the SOE—the problem of keying material
>> distribution was too great. Instead, they used worked-out keys which were
>> destroyed after each use.
> In the talk he made it sound like OTP became a real thing, but he also still seemed exasperated, decades later, at how hard it was to deal with the companies who produced the printed silk the SOE agents needed. (I bet they kept violating the clearly silly one-time aspect.) The WOK was much more frugal with key material, possibly OTP was always more his goal than ever a working reality. After all, the title of the book, /Between Silk and Cyanide/, is the tension between the value of silk vs the value of the SOE agent's life.
>

During the war, silk was a scarce material and was needed for, among other things, parachutes. (But it's a fair number of years since I read the book, and of course a lot of it was about the political infighting in London—the NY Times doesn't normally review books for their deep technical content interesting to folks like us…)

        —Steve Bellovin, https://www.cs.columbia.edu/~smb