Where Would You Find Both ECC and RSA Working Well Together? Well, In Virtually Every Web Connection
Don’t you sometimes worry that we use the Internet and don’t actually understand how it works? Well, let’s dive into the wonderful world of key exchanges, and which are the core of every TLS connection that we make to the Web.
ECDH (Elliptic Curve Diffie Hellman)
For key exchange, we started with the wonderful Diffie-Hellman method. This used discrete logs, and where Alice generated a secret value (a) and passed g^a (mod p) to Bob. Bob generated b and passed g^b (mod p). They then ended up with the same shared secret of g^{ab} (mod p). But discrete logs have struggled to scale up, and we need fairly large values of p.
Thus ECC (Elliptic Curve Cryptography) came along and allowed Alice to generate a secret (a), and then a public key point of a.G. Bob did the same and generated b and b.G. They then pass their public key points and end with the same value a.b.G:
