[petteyg359]

I'm trying to write a client program that connects to a server with Diffie Hellman encryption. I've got two problems.

1. I can't find any examples using C/C++ and DH for connecting to a server. I've found lots of examples that create two DH objects inside the same program, that can "communicate" with each other, but nothing that actually opens a socket and connects to a server running on a different system.

2. The server's prime "key" for DH is already known. It is 128 bits long. How does one deal with 128-bit integers, when the largest type is uint64_t?

[johan851]

Not sure how to help with the C/C++ socket stuff, because I'm not knowledgeable there. Still, it seems that if you know how to do network communication, then the examples of a DH client within one program should be all you need.

Typically long keys are stored as arrays of bytes, not as a single integer. That gives you more flexibility if you want to bump up your key length later. Sometimes DH keys can be quite large - 1024 or 2048 bits.

[ShadowPho]

Originally Posted by petteyg359

I'm trying to write a client program that connects to a server with Diffie Hellman encryption. I've got two problems.

1. I can't find any examples using C/C++ and DH for connecting to a server. I've found lots of examples that create two DH objects inside the same program, that can "communicate" with each other, but nothing that actually opens a socket and connects to a server running on a different system.

2. The server's prime "key" for DH is already known. It is 128 bits long. How does one deal with 128-bit integers, when the largest type is uint64_t?

1) winsock.