Documentation
¶
Index ¶
- Constants
- Variables
- func DecodeProof(pi []byte) (r *ed.ExtendedGroupElement, c *[N2]byte, s *[N2]byte, err error)
- func ECP2OS(P *ed.ExtendedGroupElement) []byte
- func ECP2OSProj(P *ed.ProjectiveGroupElement) []byte
- func F2IP(f *[32]byte) *big.Int
- func G() *ed.ExtendedGroupElement
- func GeAdd(p, qe *ed.ExtendedGroupElement) *ed.ExtendedGroupElement
- func GeDouble(p *ed.ExtendedGroupElement) *ed.ExtendedGroupElement
- func GeScalarMult(h *ed.ExtendedGroupElement, a *[32]byte) *ed.ExtendedGroupElement
- func GeneratePkWithSk(sk string) (PublicKey, PrivateKey, error)
- func I2OSP(b *big.Int, n int) []byte
- func IP2F(b *big.Int) *[32]byte
- func OS2ECP(os []byte, sign byte) *ed.ExtendedGroupElement
- func OS2IP(os []byte) *big.Int
- func S2OS(s []byte) []byte
- func ToCached(r *CachedGroupElement, p *ed.ExtendedGroupElement)
- type CachedGroupElement
- type Ed25519VRF
- func (vrf Ed25519VRF) Generate(pk PublicKey, sk PrivateKey, msg []byte) (proof []byte, err error)
- func (vrf Ed25519VRF) GenerateKey(rnd io.Reader) (pk PublicKey, sk PrivateKey, err error)
- func (vrf Ed25519VRF) ProofToHash(proof []byte) []byte
- func (vrf Ed25519VRF) VRF(pk PublicKey, sk PrivateKey, msg []byte) (hash []byte, proof []byte, err error)
- func (vrf Ed25519VRF) VerifyProof(pk PublicKey, proof []byte, msg []byte) (bool, error)
- type PrivateKey
- type PublicKey
- type VRF
Constants ¶
const ( // PublicKeySize is the size, in bytes, of public keys as used in this package. PublicKeySize = 32 // PrivateKeySize is the size, in bytes, of private keys as used in this package. PrivateKeySize = 64 )
const ( // N2 is a necessary parameter for ed25519 algorithm N2 = 32 // ceil(log2(qs) / 8) // N is a necessary parameter for ed25519 algorithm N = N2 / 2 NOSIGN = 3 )
Variables ¶
var ( // ErrMalformedInput returns the error of malformed input. ErrMalformedInput = errors.New("ECVRF: malformed input") // ErrDecodeError returns the error of failed to decode proof. ErrDecodeError = errors.New("ECVRF: decode error") )
Functions ¶
func DecodeProof ¶
DecodeProof decode from bytes to VRF proof.
func ECP2OS ¶
func ECP2OS(P *ed.ExtendedGroupElement) []byte
func ECP2OSProj ¶
func ECP2OSProj(P *ed.ProjectiveGroupElement) []byte
func G ¶
func G() *ed.ExtendedGroupElement
func GeAdd ¶
func GeAdd(p, qe *ed.ExtendedGroupElement) *ed.ExtendedGroupElement
func GeDouble ¶
func GeDouble(p *ed.ExtendedGroupElement) *ed.ExtendedGroupElement
func GeScalarMult ¶
func GeScalarMult(h *ed.ExtendedGroupElement, a *[32]byte) *ed.ExtendedGroupElement
func GeneratePkWithSk ¶
func GeneratePkWithSk(sk string) (PublicKey, PrivateKey, error)
GeneratePkWithSk generates KeyPair With sk(string)
func ToCached ¶
func ToCached(r *CachedGroupElement, p *ed.ExtendedGroupElement)
Types ¶
type CachedGroupElement ¶
type CachedGroupElement struct {
Z, T2d ed.FieldElement
// contains filtered or unexported fields
}
CachedGroupElement is copied from ed.go and const.go in golang.org/x/crypto/ed25519/internal/ed
type Ed25519VRF ¶
type Ed25519VRF struct{}
func (Ed25519VRF) Generate ¶
func (vrf Ed25519VRF) Generate(pk PublicKey, sk PrivateKey, msg []byte) (proof []byte, err error)
Generate proof of given msg.
PublicKey and PrivateKey must be generated from EC25519, i.e. ed25519.GenerateKey()
Steps: 1. h = hash_to_curve(suite, y, seed) 2. h1 = EC2OSP(h) 3. gamma = h^x 4. k = nonce_generation(sk, h1) 5. c = hash_points(h, gamma, g^k, h^k) 6. s = (k + c * x) mod q (* = integer multiplication) 7. output = EC2OSP(gamma) || I2OSP(c, n) || I2OSP(s, 2n)
func (Ed25519VRF) GenerateKey ¶
func (vrf Ed25519VRF) GenerateKey(rnd io.Reader) (pk PublicKey, sk PrivateKey, err error)
GenerateKey creates a public/private key pair. rnd is used for randomness. If it is nil, `crypto/rand` is used.
func (Ed25519VRF) ProofToHash ¶
func (vrf Ed25519VRF) ProofToHash(proof []byte) []byte
ProofToHash generates hash from given proof.
Steps: 1. (gamma, c, s) = decode_proof(pi) 2. three = 0x03 = I2OSP(3, 1) 3. preBeta = Hash(suite || three || EC2OSP(gamma ^cofactor)) 4. output = first 2n octets of preBeta
func (Ed25519VRF) VRF ¶
func (vrf Ed25519VRF) VRF(pk PublicKey, sk PrivateKey, msg []byte) (hash []byte, proof []byte, err error)
VRF returns the proof and its hash.
func (Ed25519VRF) VerifyProof ¶
VerifyProof verifies the proof given seed.
Steps:
- (gamma, c, s) = decode(pi)
- u = g^s / y^c (where / denotes EC point subtraction, i.e. the group operation applied to g^s and the inverse of y^c
- h = hash_to_curve(suite, y, seed)
- v = h^s * gamma^c
- c'= hash_points(h, gamma, u, v)
- output = (c == c')
type PrivateKey ¶
type PrivateKey []byte
PrivateKey defines to be private key data structure of MultiVAC account.
type PublicKey ¶
type PublicKey []byte
PublicKey defines to be public key data structure of MultiVAC account.
type VRF ¶
type VRF interface {
// GenerateKey creates a public/private key pair. rnd is used for randomness.
//
// If rnd is nil, 'crypto/rand' is used.
GenerateKey(rnd io.Reader) (pk PublicKey, sk PrivateKey, err error)
// Generates a proof with given private key and public key.
//
// Note: the public key is not necessary. Just for efficiency.
Generate(pk PublicKey, sk PrivateKey, msg []byte) (proof []byte, err error)
// Verifies the proof is indeed for given message.
//
// Notice that the PublicKey belongs to the broadcaster of the RNG, not the node itself.
VerifyProof(publicKey PublicKey, pf []byte, msg []byte) (res bool, err error)
// Renders hash from proof.
ProofToHash(pf []byte) []byte
// TODO Clean up the API and update test for this.
// Generates hash and its proof
VRF(pk PublicKey, sk PrivateKey, msg []byte) (hash []byte, proof []byte, err error)
}
VRF is named Verifiable Random Function. See https://en.wikipedia.org/wiki//Verifable_random_function for more info.
This class is overall in charge of all functionalities related to VRF, including generating RNG, verification, etc.
VRF is designed to be a stateless oracle(like how it was originally designed). Caller is responsible for rendering the private key.
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