Library for RSA implementation in pure C

Question

I'm looking for a very simple implementation of RSA in C. I need to place it in a DSP, so I'd like to use something very thin and straightforward. Nonetheless, I just found only examples with little numbers (int or long) while I need to implement RSA at least at 1024 bits, so I also have to cope with large numbers.

Can you point me to some libraries or examples for this?

Answer 1

The LibTomCrypt and related projects are very clean and understandable.

Answer 2

The latest openssl release's source contains an implementation of RSA, which should work fine for your purposes. Alternatively, you may also consider the GNUPg project, another open-source project with an RSA component.