UltraVNC

I agree DH can be slow, and it depends on hardware which gets faster every day. I remember 64-bit encryption being "unthinkable" to break.

Maybe the solution is to add a parameter to let to user adjust depending on their hardware?

For example, this could prevent PcHelpWare from becoming obsolete ...

I'm trying to recommend PCHelpWare 1.0 but I'm being blocked due to perception of weak security.

Two simple changes would eliminate all arguments:

1. Change Diffie–Hellman from 512-bit to 2048-bit.
2. Change MD5 to SHA-256 (truncate to 128 bits if needed)

I'm told that using 512-bit DH for key ...