一篇文章搞懂VRF

// A VRF is a pseudorandom function f_k from a secret key k, such that that
// knowledge of k not only enables one to evaluate f_k at for any message m,
// but also to provide an NP-proof that the value f_k(m) is indeed correct
// without compromising the unpredictability of f_k for any m' != m.
// http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=814584

// PrivateKey supports evaluating the VRF function.
type PrivateKey interface {
	// Evaluate returns the output of H(f_k(m)) and its proof.
	Evaluate(m []byte) (index [32]byte, proof []byte)
	// Public returns the corresponding public key.
	Public() crypto.PublicKey
}

// PublicKey supports verifying output from the VRF function.
type PublicKey interface {
	// ProofToHash verifies the NP-proof supplied by Proof and outputs Index.
	ProofToHash(m, proof []byte) (index [32]byte, err error)
}

func TestVRFForS256(t *testing.T) {
    //私钥持有人
	key, err := crypto.GenerateKey()
	if err != nil {
		t.Error(err)
		return
	}
	k, err := NewVRFSigner(key)
	if err != nil {
		t.Error(err)
		return
    }
    //验证人,只知道公钥
	pk, err := NewVRFVerifier(&key.PublicKey)
	if err != nil {
		t.Error(err)
		return
	}
	msg := []byte("data1")
	index, proof := k.Evaluate(msg)
	index2, err := pk.ProofToHash(msg, proof)

	if err != nil {
		t.Error(err)
	}
	if index2 != index {
		t.Error("index not equal")
	}

}