My question is about the client and server performance for (EC)DHE.
I am having difficulties in understanding this picture (which is based on numbers from Ivan Ristic’ book “Bulletproof SSL and TLS”).
Let’s start with the third row “RSA 2048, DHE 2048”. I can understand that client and server computation times differ because creating a signature is different from verifying it.
I understand that ECDHE is faster than DHE and therefore the numbers in the second row are smaller than the ones in the third row.
My questions are:
- The effort for DHE and ECDHE is identical for client and server, isn’t it?
- Why is the client’s computation time for “RSA 2048, ECDHE 256” smaller than the server’s while for “RSA 2048, DHE 2048” it is the other way around?