For example, fig 4.7, 4.8 shows in
Seems like a task TikZ could perfectly handle. Those examples could help you get started (I did not find any pure cryptographic example, but feel free to contribute once you've created yours!).
http://www.di.ens.fr/~jean/latex_crypto/ has many examples of cryptographic diagrams in TikZ which you can use or adapt.
A bit late but this is an excellent resource: https://www.iacr.org/authors/tikz/