I need to use “ECDH with a cofactor key” for generating symmetric key. I have a fair idea on how ECDH works, but I don’t understand the cofactor part.
What is the difference between ”ECDH with a co-factor key” and ”ECDH without a co-factor key”?
Also, it would be great if you could point me to information related to the implementation itself.
Nota Bene: my related StackOverflow question got closed and I was advised to ask at Crypto.SE.