The book Between Silk and Cyanide had a good bit about clothing including one-time-pads written on silk and stitched into the lining of clothing, and buttons th

The book Between Silk and Cyanide had a good bit about clothing including one-time-pads written on silk and stitched into the lining of clothing, and buttons that could do double duty for different disguises (like one side British, one side German). Probably my favorite book so far about WWII and codebreaking (though the Colditz book is a great read too).