Vanadium的小屋

Lecture 1

Cryptograhpy = hidden to write

Syntax

Gen(Random) -> sk // Randomized Algo.
Enc(sk, M) -> C // Both
Dec(sk, C) -> M // Deterministic Algo.

sk: Secret Key

How to Define CORRECTNESS

M: Message Space
K: Secret Ket Space

$\forall m\in M,Pr[Dec(Enc(sk,m)) = m] = 1$

Power of Adversary

Can the adversary know (Gen, Enc, Dec)?

The security of cryptosystems only depends that secret key is protected — August Kerchoff’s Principle

Provable Security

1. Security Defination
2. Mathematic Assumpiton
3. Reduction 归约

以公认的数学难题为背书，归约/包装到安全算法