secp256k1

Documentation

Index

• Constants
• func RecoverFromAdaptorAndSignature(adaptor *EncryptedSignature, encryptionKey *PublicKey, sig *Signature) (*secp256k1.ModNScalar, error)
• type EncryptedSignature
  • func (s *EncryptedSignature) Decode(b []byte) error
  • func (a *EncryptedSignature) Decrypt(sk *secp256k1.ModNScalar) (*Signature, error)
  • func (s *EncryptedSignature) Encode() ([]byte, error)
  • func (s *EncryptedSignature) MarshalJSON() ([]byte, error)
  • func (s *EncryptedSignature) UnmarshalJSON(in []byte) error
• type Keypair
  • func GenerateKeypair() *Keypair
  • func KeypairFromHex(s string) *Keypair
  • func (kp *Keypair) AdaptorSign(msg []byte, encKey *PublicKey, nonceFnOpt ...NonceFunc) (*EncryptedSignature, error)
  • func (kp *Keypair) Private() *PrivateKey
  • func (kp *Keypair) Public() *PublicKey
  • func (kp *Keypair) Sign(msg []byte) (*Signature, error)
• type NonceFunc
  • func WithRFC6979(sk *PrivateKey, msg []byte, encKey *PublicKey) NonceFunc
  • func WithRandom() NonceFunc
• type Point
  • func (p *Point) Add(a, b *Point)
  • func (p *Point) BaseExp(k *secp256k1.ModNScalar)
  • func (p *Point) Copy() *Point
  • func (p *Point) Equal(other *Point) bool
  • func (p *Point) Negate()
  • func (p *Point) PutBytes(dst []byte)
  • func (p *Point) Scale(point *Point, k *secp256k1.ModNScalar)
  • func (p *Point) SetBytes(bc []byte) error
  • func (p *Point) Sub(a, b *Point)
  • func (p *Point) ToBytes() []byte
  • func (p *Point) XY() (*secp256k1.FieldVal, *secp256k1.FieldVal, error)
• type PrivateKey
  • func (k *PrivateKey) Decode(b []byte) error
  • func (k *PrivateKey) Encode() ([]byte, error)
  • func (k *PrivateKey) Inner() *secp256k1.ModNScalar
  • func (k *PrivateKey) MarshalJSON() ([]byte, error)
  • func (k *PrivateKey) Public() *PublicKey
  • func (k *PrivateKey) UnmarshalJSON(in []byte) error
• type PublicKey
  • func (k *PublicKey) Decode(b []byte) error
  • func (k *PublicKey) Encode() ([]byte, error)
  • func (k *PublicKey) EncodeDecompressed() ([]byte, error)
  • func (k *PublicKey) MarshalJSON() ([]byte, error)
  • func (k *PublicKey) UnmarshalJSON(in []byte) error
  • func (k *PublicKey) Verify(msg []byte, sig *Signature) (bool, error)
  • func (k *PublicKey) VerifyAdaptor(msg []byte, encryptionKey *PublicKey, adaptor *EncryptedSignature) (bool, error)
• type Signature
  • func (s *Signature) Decode(b []byte) error
  • func (s *Signature) Encode() ([]byte, error)
  • func (s *Signature) EncodeRecoverable() ([]byte, error)
  • func (s *Signature) MarshalJSON() ([]byte, error)
  • func (s *Signature) UnmarshalJSON(in []byte) error

Constants

const EncodedAdaptorSize = 33 + 33 + (32 * 3)

const MessageLength = 32

Functions

func RecoverFromAdaptorAndSignature

func RecoverFromAdaptorAndSignature(adaptor *EncryptedSignature, encryptionKey *PublicKey, sig *Signature) (*secp256k1.ModNScalar, error)

RecoverFromAdaptorAndSignature recovers the decryption key given an encrypted signature and the signature that was decrypted from it.

Types

type EncryptedSignature

type EncryptedSignature struct {
	R, R_a *Point
	// contains filtered or unexported fields
}

EncryptedSignature is an "encrypted" ECDSA signature aka adaptor signature (R || R_a || s || dleqProof).

func (*EncryptedSignature) Decode

func (s *EncryptedSignature) Decode(b []byte) error

Decode parses bytes buffer `b` into EncryptedSignature.

func (*EncryptedSignature) Decrypt

func (a *EncryptedSignature) Decrypt(sk *secp256k1.ModNScalar) (*Signature, error)

Decrypt function is used to decrypt an encrypted signature yielding the plain ECDSA signature.

* Before calling this method you should be certain that the EncryptedSignature is what you think it is by calling PublicKey.VerifyAdaptor on it first.

* Once you give the decrypted Signature to anyone who has seen EncryptedSignature, they will be able to learn decryption key aka secret by calling RecoverFromAdaptorAndSignature.

func (*EncryptedSignature) Encode

func (s *EncryptedSignature) Encode() ([]byte, error)

Encode encodes EncryptedSignature into EncodedAdaptorSize bytes buffer as follows (R || R_a || s || proof.z | proof.s).

func (*EncryptedSignature) MarshalJSON

func (s *EncryptedSignature) MarshalJSON() ([]byte, error)

MarshalJSON serializes EncryptedSignature into JSON format based on the Encode method.

func (*EncryptedSignature) UnmarshalJSON

func (s *EncryptedSignature) UnmarshalJSON(in []byte) error

UnmarshalJSON deserializes EncryptedSignature from JSON formatted bytes based on the Decode method.

type Keypair

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

Keypair defines pair of ECDSA PrivateKey and PublicKey.

func GenerateKeypair

func GenerateKeypair() *Keypair

GenerateKeypair generates a random PrivateKey scalar and derives point on secp256k1 curve as a corresponding PublicKey. If private scalar generates no point on a curve, this step would be repeated until it is.

func KeypairFromHex

func KeypairFromHex(s string) *Keypair

KeypairFromHex decodes hex formatted (without "0x") string `s` into a Keypair.

func (*Keypair) AdaptorSign

func (kp *Keypair) AdaptorSign(msg []byte, encKey *PublicKey, nonceFnOpt ...NonceFunc) (*EncryptedSignature, error)

AdaptorSign create an encrypted signature aka "adaptor signature" aka "pre-signature".

The `msg` param is a 32 bytes hash. Use `nonceFnOpt` to specify custom NonceFunc. Default is WithRFC6979.

func (*Keypair) Private

func (kp *Keypair) Private() *PrivateKey

Private returns PrivateKey component.

func (*Keypair) Public

func (kp *Keypair) Public() *PublicKey

Public returns PublicKey component.

func (*Keypair) Sign

func (kp *Keypair) Sign(msg []byte) (*Signature, error)

Sign performs ECDSA signing of the 32 bytes `msg` hash.

If `msg` length overflows 32 bytes error will be returned.

type NonceFunc

type NonceFunc = func() (*secp256k1.ModNScalar, error)

NonceFunc defines nonce generation algorithm.

func WithRFC6979

func WithRFC6979(sk *PrivateKey, msg []byte, encKey *PublicKey) NonceFunc

WithRFC6979 can be used to specify deterministic nonce generation based on the RFC-6979 spec.

This is the default way of generation nonce in this library.

func WithRandom

func WithRandom() NonceFunc

WithRandom can be used to specify random nonce generation.

type Point

type Point struct {
	*secp256k1.JacobianPoint
}

Point is the library's internal elliptic curve point representation and is a wrapper around `secp256k1.JacobianPoint` https://github.com/decred/dcrd/tree/master/dcrec/secp256k1.

func (*Point) Add

func (p *Point) Add(a, b *Point)

func (*Point) BaseExp

func (p *Point) BaseExp(k *secp256k1.ModNScalar)

func (*Point) Copy

func (p *Point) Copy() *Point

func (*Point) Equal

func (p *Point) Equal(other *Point) bool

func (*Point) Negate

func (p *Point) Negate()

func (*Point) PutBytes

func (p *Point) PutBytes(dst []byte)

func (*Point) Scale

func (p *Point) Scale(point *Point, k *secp256k1.ModNScalar)

func (*Point) SetBytes

func (p *Point) SetBytes(bc []byte) error

func (*Point) Sub

func (p *Point) Sub(a, b *Point)

func (*Point) ToBytes

func (p *Point) ToBytes() []byte

func (*Point) XY

func (p *Point) XY() (*secp256k1.FieldVal, *secp256k1.FieldVal, error)

type PrivateKey

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

PrivateKey wraps secp256k1 scalar field being a secret component of the ECDSA scheme.

func (*PrivateKey) Decode

func (k *PrivateKey) Decode(b []byte) error

Decode parses bytes buffer `b` into PrivateKey.

If buffer overflows 32 bytes error will be returned.

func (*PrivateKey) Encode

func (k *PrivateKey) Encode() ([]byte, error)

Encode encodes PrivateKey into a 32 bytes buffer.

func (*PrivateKey) Inner

func (k *PrivateKey) Inner() *secp256k1.ModNScalar

Inner returns secp256k1.ModNScalar behind PrivateKey.

func (*PrivateKey) MarshalJSON

func (k *PrivateKey) MarshalJSON() ([]byte, error)

MarshalJSON serializes PrivateKey into JSON format based on the Encode method.

func (*PrivateKey) Public

func (k *PrivateKey) Public() *PublicKey

Public derives PublicKey (X) by generating point with secret scalar (x): X = G^x.

func (*PrivateKey) UnmarshalJSON

func (k *PrivateKey) UnmarshalJSON(in []byte) error

UnmarshalJSON deserializes JSON formatted bytes into PrivateKey.

type PublicKey

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

PublicKey wraps point on the secp256k1 curve being a public component of the ECDSA scheme.

func (*PublicKey) Decode

func (k *PublicKey) Decode(b []byte) error

Decode decodes bytes buffer `b` into a PublicKey automatically recognizing compression type.

func (*PublicKey) Encode

func (k *PublicKey) Encode() ([]byte, error)

Encode encodes PublicKey into a 33 bytes buffer in a compressed form.

To comply with go-ethereum requirements first byte specifies this "type" (ie. compressed, uncompressed, or hybrid) https://github.com/quan8/go-ethereum/blob/a1c09b93871dd3770adffb177086abda1b2ff3af/vendor/github.com/btcsuite/btcd/btcec/pubkey.go#L69

func (*PublicKey) EncodeDecompressed

func (k *PublicKey) EncodeDecompressed() ([]byte, error)

EncodeDecompressed encodes PublicKey into a 64 bytes buffer in an uncompressed form (x||y).

func (*PublicKey) MarshalJSON

func (k *PublicKey) MarshalJSON() ([]byte, error)

MarshalJSON serializes PublicKey into JSON format based on the Encode method.

func (*PublicKey) UnmarshalJSON

func (k *PublicKey) UnmarshalJSON(in []byte) error

UnmarshalJSON deserializes JSON formatted bytes into PublicKey.

func (*PublicKey) Verify

func (k *PublicKey) Verify(msg []byte, sig *Signature) (bool, error)

Verify verifies that given Signature was signed from a `msg` by the receiver PublicKey.

func (*PublicKey) VerifyAdaptor

func (k *PublicKey) VerifyAdaptor(msg []byte, encryptionKey *PublicKey, adaptor *EncryptedSignature) (bool, error)

VerifyAdaptor verifies an encrypted signature is valid i.e. if it is decrypted it will yield a signature on `msg` under receiver PublicKey.

type Signature

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

Signature is a standard ECDSA signature (v||r||s).

func (*Signature) Decode

func (s *Signature) Decode(b []byte) error

Decode parses 64/65 bytes buffer `b` into a receiver Signature.

In case `b` is 65 bytes the last 65-th byte would be decoded as `recovery_id` aka `v`.

func (*Signature) Encode

func (s *Signature) Encode() ([]byte, error)

Encode encodes Signature into a 64 bytes buffer.

func (*Signature) EncodeRecoverable

func (s *Signature) EncodeRecoverable() ([]byte, error)

EncodeRecoverable encodes Signature into a 65 bytes buffer where last byte is a `receiver_id` aka `v`.

func (*Signature) MarshalJSON

func (s *Signature) MarshalJSON() ([]byte, error)

MarshalJSON serializes Signature into JSON format based on the Encode method.

func (*Signature) UnmarshalJSON

func (s *Signature) UnmarshalJSON(in []byte) error

UnmarshalJSON deserializes JSON formatted bytes into Signature.