Shared secret computation

[robertsdotpm]

Hello,

Just a quick question:

I see in the code that a shared point is computed

shared_point = peer_public_key.multiply(private_key.secret)

But then the public key is added to the shared point. Why is that last step necessary? I looked at ECDH and it just mentioned the first steps (the multiply.) Is the add necessary?

[kigawas]

It's just a choice, shared point only is also fine. Since we use KDF to derive the symmetric key, longer (ie more entropy) is better