📦 Be sure to check out the NuGet pacakge: https://www.nuget.org/packages/NTDLS.SecureKeyExchange
Easily generate a shared diffie-hellman key in C++ or C#.
Scenerio (use your imagination):
- localHost is a local service.
- remotePeer is a remote peer.
//localHost starts the process with a call to GenerateNegotiationToken(),
// specifying the size of the key (which is actually n*12).
var localHost = new CompoundNegotiator();
byte[] negotiationToken = localHost.GenerateNegotiationToken(8);
//localHost passes the resulting bytes from GenerateNegotiationToken()
// to a remote peer which passes the bytes to ApplyNegotiationToken().
var remotePeer = new CompoundNegotiator();
byte[] negotiationReply = remotePeer.ApplyNegotiationToken(negotiationToken);
//The remotePeer passes the bytes from ApplyNegotiationToken() back to the
// localHost, where the localHost passes them to ApplyNegotiationResponseToken()
localHost.ApplyNegotiationResponseToken(negotiationReply);
//At this point, both the localHost and the remotePeer have the same bytes in
// "SharedSecret" as we can see from comparing the "SharedSecretHash".
if (remotePeer.SharedSecretHash != localHost.SharedSecretHash)
{
throw new Exception("This should never happen.");
}
Console.WriteLine($"Key length: {localHost.KeyLength} bytes.");
Console.WriteLine($" Local Shared Secret: {localHost.SharedSecretHash}");
Console.WriteLine($"Remote Shared Secret: {remotePeer.SharedSecretHash}");