2.8.4 Public Key Encryption

Public key encryption is a much slower alternative to private key; separates authentication from secrecy.

Each key is a pair K,K-1

With private key: (text)$\wedge$K$\wedge$K = text

With public key:

• (text)$\wedge$K$\wedge$K-1 = text, but (text)$\wedge$K$\wedge$K $\neq$ text

• (text)$\wedge$K-1$\wedge$K = text, but (text)$\wedge$K-1$\wedge$K-1 $\neq$ text

Can't derive K from K-1, or vice versa