ring

README

ring-go

Implementation of linkable ring signatures using elliptic curve crypto in pure Go. It supports ring signatures over both ed25519 and secp256k1.

requirements

go 1.19

get

go get github.com/noot/ring-go

references

This implementation is based off of Ring Confidential Transactions, in particular section 2, which defines MLSAG (Multilayered Linkable Spontaneous Anonymous Group signatures).

usage

See examples/main.go.

package main

import (
	"fmt"

	ring "github.com/noot/ring-go"
	"golang.org/x/crypto/sha3"
)

func signAndVerify(curve ring.Curve) {
	privkey := curve.NewRandomScalar()
	msgHash := sha3.Sum256([]byte("helloworld"))

	// size of the public key ring (anonymity set)
	const size = 16

	// our key's secret index within the set
	const idx = 7
	
	keyring, err := ring.NewKeyRing(curve, size, privkey, idx)
	if err != nil {
		panic(err)
	}

	sig, err := keyring.Sign(msgHash, privkey)
	if err != nil {
		panic(err)
	}

	ok := sig.Verify(msgHash)
	if !ok {
		fmt.Println("failed to verify :(")
		return
	}

	fmt.Println("verified signature!")
}

func main() {
	fmt.Println("using secp256k1...")
	signAndVerify(ring.Secp256k1())
	fmt.Println("using ed25519...")
	signAndVerify(ring.Ed25519())
}

Documentation

Index

• func Ed25519() types.Curve
• func Link(sigA, sigB *RingSig) bool
• func Secp256k1() types.Curve
• type Curve
• type Ring
  • func NewFixedKeyRingFromPublicKeys(curve types.Curve, pubkeys []types.Point) (*Ring, error)
  • func NewKeyRing(curve types.Curve, size int, privkey types.Scalar, idx int) (*Ring, error)
  • func NewKeyRingFromPublicKeys(curve types.Curve, pubkeys []types.Point, privkey types.Scalar, idx int) (*Ring, error)
  • func (ring *Ring) Equals(other *Ring) bool
  • func (r *Ring) Sign(m [32]byte, privkey types.Scalar) (*RingSig, error)
  • func (r *Ring) Size() int
• type RingSig
  • func Sign(m [32]byte, ring *Ring, privkey types.Scalar, ourIdx int) (*RingSig, error)
  • func (sig *RingSig) Deserialize(curve Curve, in []byte) error
  • func (r *RingSig) PublicKeys() []types.Point
  • func (r *RingSig) Ring() *Ring
  • func (r *RingSig) Serialize() ([]byte, error)
  • func (sig *RingSig) Verify(m [32]byte) bool

Functions

func Ed25519

func Ed25519() types.Curve

Ed25519 returns a new ed25519 curve instance.

func Link

func Link(sigA, sigB *RingSig) bool

Link returns true if the two signatures were created by the same signer, false otherwise.

func Secp256k1

func Secp256k1() types.Curve

Secp256k1 returns a new secp256k1 curve instance

Types

type Curve

type Curve = types.Curve

Curve represents an elliptic curve that can be used for signing.

type Ring

type Ring struct {
	// contains filtered or unexported fields
}

Ring represents a group of public keys such that one of the group created a signature.

func NewFixedKeyRingFromPublicKeys

func NewFixedKeyRingFromPublicKeys(curve types.Curve, pubkeys []types.Point) (*Ring, error)

NewFixedKeyRingFromPublicKeys takes public keys and a curve to create a ring

func NewKeyRing

func NewKeyRing(curve types.Curve, size int, privkey types.Scalar, idx int) (*Ring, error)

NewKeyRing creates a ring with size specified by `size` and places the public key corresponding to `privkey` in index idx of the ring. It returns a ring of public keys of length `size`.

func NewKeyRingFromPublicKeys

func NewKeyRingFromPublicKeys(curve types.Curve, pubkeys []types.Point, privkey types.Scalar, idx int) (*Ring, error)

NewKeyRingFromPublicKeys takes public key ring and places the public key corresponding to `privkey` in index idx of the ring. It returns a ring of public keys of length `len(ring)+1`.

func (*Ring) Equals

func (ring *Ring) Equals(other *Ring) bool

Equals checks whether the supplied ring is equal to the current ring. The ring's public keys must be in the same order for the rings to be equal

func (*Ring) Sign

func (r *Ring) Sign(m [32]byte, privkey types.Scalar) (*RingSig, error)

Sign creates a ring signature on the given message using the public key ring and a private key of one of the members of the ring.

func (*Ring) Size

func (r *Ring) Size() int

Size returns the size of the ring, ie. the number of public keys in it.

type RingSig

type RingSig struct {
	// contains filtered or unexported fields
}

RingSig represents a ring signature.

func Sign

func Sign(m [32]byte, ring *Ring, privkey types.Scalar, ourIdx int) (*RingSig, error)

Sign creates a ring signature on the given message using the provided private key and ring of public keys.

func (*RingSig) Deserialize

func (sig *RingSig) Deserialize(curve Curve, in []byte) error

Deserialize converts the byteified signature into a *RingSig.

func (*RingSig) PublicKeys

func (r *RingSig) PublicKeys() []types.Point

PublicKeys returns a copy of the ring signature's public keys.

func (*RingSig) Ring

func (r *RingSig) Ring() *Ring

Ring returns the ring from the RingSig struct

func (*RingSig) Serialize

func (r *RingSig) Serialize() ([]byte, error)

Serialize converts the signature to a byte array.

func (*RingSig) Verify

func (sig *RingSig) Verify(m [32]byte) bool

Verify verifies the ring signature for the given message. It returns true if a valid signature, false otherwise.