As a side project, to support remote mail and news pickup through the Internet to my company's servers (through a firewall), I've been slowly writing an end-to-end encryption program. Essentially, the idea is that the client program (say, a mail program) connects to a client "reflector", which lives on the same person's machine. The client reflector connects to a server reflector, which perhaps lives on the firewall. The client and server talk to each other, the client is authenticated, and the session key is agreed upon. Then the server reflector connects to the server process (say, smtpd, probably on some machine inside the company's net), and an encypted session is obtained. This doesn't protect against the machine's memory being watched or anything like that, but it does provide a good amount of security for packets over the Internet, just like the end-to-end type of encryption software described in Applied Cryptography. Now, this is my first code with any real encryption in it, and I'm trying to tackle key negotiation protocols and so on, while at the same time utilizing RSA, IDEA and MD5. In my research, I found that a number of firewall vendors have such a system available, either implemented in hardware or software. What I want to know is: Is there any code like this available somewhere on the net that does this stuff? I would hate to have to reinvent the wheel if I don't have to, given my limited amount of spare time.