Public Key Encryption in ANSI C

Hi

Does anyone know where I can get ANSI C source for public key encryption? I want to implement in VC6 and also on 68k based embedded firmware.

The background -
I'm thinking about a project where I have VC6 application communicating with a peripheral that has a 68k based embedded controller card (and no operating system).
The application and the peripheral are both on an Ethernet network that is shared with other PCs.
I can pass data between my app and the peripheral OK but I want to secure the data from the peripheral to the app.
VGirish gives an excellent link to AES that has source that I could implement in both VC application and embedded 68k. The problem with AES is that I have to load both ends with the key - theoretically not a problem but difficult in practice (68k end has no keyboard!).
A public key solution would be much better, the VC application could request data from the peripheral and provide the public key.

Thanks

Alec

The OpenSSL (www.openssl.org) library is a very good start. I think it has every thing you need for doing Public Key encryption (PKI in general).

Good luck.