crypto

Documentation

Overview

Package crypto implements the cryptography used in the Cashu protocol as explained in Cashu.

Index

• Constants
• func BlindMessage(secret string, r *secp256k1.PrivateKey) (*secp256k1.PublicKey, *secp256k1.PrivateKey, error)
• func DeriveKeysetId(keyset map[uint64]*secp256k1.PublicKey) string
• func DeriveKeysetPath(key *hdkeychain.ExtendedKey, index uint32) (*hdkeychain.ExtendedKey, error)
• func GenerateDLEQ(a *secp256k1.PrivateKey, B_ *secp256k1.PublicKey, C_ *secp256k1.PublicKey) (*secp256k1.PrivateKey, *secp256k1.PrivateKey)
• func HashE(publicKeys []*secp256k1.PublicKey) [32]byte
• func HashToCurve(message []byte) (*secp256k1.PublicKey, error)
• func MapPubKeys(keys nut01.KeysMap) (map[uint64]*secp256k1.PublicKey, error)
• func SignBlindedMessage(B_ *secp256k1.PublicKey, k *secp256k1.PrivateKey) *secp256k1.PublicKey
• func UnblindSignature(C_ *secp256k1.PublicKey, r *secp256k1.PrivateKey, K *secp256k1.PublicKey) *secp256k1.PublicKey
• func Verify(secret string, k *secp256k1.PrivateKey, C *secp256k1.PublicKey) bool
• func VerifyDLEQ(e *secp256k1.PrivateKey, s *secp256k1.PrivateKey, A *secp256k1.PublicKey, ...) bool
• type KeyPair
  • func (kp *KeyPair) MarshalJSON() ([]byte, error)
  • func (kp *KeyPair) UnmarshalJSON(data []byte) error
• type KeyPairTemp
• type KeysetTemp
• type KeysetsMap
• type MintKeyset
  • func GenerateKeyset(master *hdkeychain.ExtendedKey, index uint32, inputFeePpk uint) (*MintKeyset, error)
  • func (ks *MintKeyset) DerivePublic() map[uint64]string
  • func (ks *MintKeyset) MarshalJSON() ([]byte, error)
  • func (ks *MintKeyset) UnmarshalJSON(data []byte) error
• type WalletKeyset
  • func (wk *WalletKeyset) MarshalJSON() ([]byte, error)
  • func (wk *WalletKeyset) UnmarshalJSON(data []byte) error
• type WalletKeysetTemp

Constants

const DomainSeparator = "Secp256k1_HashToCurve_Cashu_"

const MAX_ORDER = 60

Functions

func BlindMessage

func BlindMessage(secret string, r *secp256k1.PrivateKey) (*secp256k1.PublicKey,
	*secp256k1.PrivateKey, error)

B_ = Y + rG

func DeriveKeysetId

func DeriveKeysetId(keyset map[uint64]*secp256k1.PublicKey) string

DeriveKeysetId returns the string ID derived from the map keyset The steps to derive the ID are: - sort public keys by their amount in ascending order - concatenate all public keys to one byte array - HASH_SHA256 the concatenated public keys - take the first 14 characters of the hex-encoded hash - prefix it with a keyset ID version byte

func DeriveKeysetPath

func DeriveKeysetPath(key *hdkeychain.ExtendedKey, index uint32) (*hdkeychain.ExtendedKey, error)

func GenerateDLEQ

func GenerateDLEQ(
	a *secp256k1.PrivateKey,
	B_ *secp256k1.PublicKey,
	C_ *secp256k1.PublicKey,
) (*secp256k1.PrivateKey, *secp256k1.PrivateKey)

func HashE

func HashE(publicKeys []*secp256k1.PublicKey) [32]byte

func HashToCurve

func HashToCurve(message []byte) (*secp256k1.PublicKey, error)

The domain separator is b"Secp256k1_HashToCurve_Cashu_" or bytes.fromhex("536563703235366b315f48617368546f43757276655f43617368755f").

func MapPubKeys

func MapPubKeys(keys nut01.KeysMap) (map[uint64]*secp256k1.PublicKey, error)

func SignBlindedMessage

func SignBlindedMessage(B_ *secp256k1.PublicKey, k *secp256k1.PrivateKey) *secp256k1.PublicKey

C_ = kB_

func UnblindSignature

func UnblindSignature(C_ *secp256k1.PublicKey, r *secp256k1.PrivateKey,
	K *secp256k1.PublicKey) *secp256k1.PublicKey

C = C_ - rK

func Verify

func Verify(secret string, k *secp256k1.PrivateKey, C *secp256k1.PublicKey) bool

k * HashToCurve(secret) == C

func VerifyDLEQ

func VerifyDLEQ(
	e *secp256k1.PrivateKey,
	s *secp256k1.PrivateKey,
	A *secp256k1.PublicKey,
	B_ *secp256k1.PublicKey,
	C_ *secp256k1.PublicKey,
) bool

Types

type KeyPair

type KeyPair struct {
	PrivateKey *secp256k1.PrivateKey
	PublicKey  *secp256k1.PublicKey
}

func (*KeyPair) MarshalJSON

func (kp *KeyPair) MarshalJSON() ([]byte, error)

func (*KeyPair) UnmarshalJSON

func (kp *KeyPair) UnmarshalJSON(data []byte) error

type KeyPairTemp

type KeyPairTemp struct {
	PrivateKey []byte `json:"private_key"`
	PublicKey  []byte `json:"public_key"`
}

type KeysetTemp

type KeysetTemp struct {
	Id          string
	Unit        string
	Active      bool
	Keys        map[uint64]json.RawMessage
	InputFeePpk uint
}

type KeysetsMap

type KeysetsMap map[string]map[string]WalletKeyset

KeysetsMap maps a mint url to map of string keyset id to keyset

type MintKeyset

type MintKeyset struct {
	Id                string
	Unit              string
	Active            bool
	DerivationPathIdx uint32
	Keys              map[uint64]KeyPair
	InputFeePpk       uint
}

func GenerateKeyset

func GenerateKeyset(master *hdkeychain.ExtendedKey, index uint32, inputFeePpk uint) (*MintKeyset, error)

func (*MintKeyset) DerivePublic

func (ks *MintKeyset) DerivePublic() map[uint64]string

DerivePublic returns the keyset's public keys as a map of amounts uint64 to strings that represents the public key

func (*MintKeyset) MarshalJSON

func (ks *MintKeyset) MarshalJSON() ([]byte, error)

func (*MintKeyset) UnmarshalJSON

func (ks *MintKeyset) UnmarshalJSON(data []byte) error

type WalletKeyset

type WalletKeyset struct {
	Id          string
	MintURL     string
	Unit        string
	Active      bool
	PublicKeys  map[uint64]*secp256k1.PublicKey
	Counter     uint32
	InputFeePpk uint
}

func (*WalletKeyset) MarshalJSON

func (wk *WalletKeyset) MarshalJSON() ([]byte, error)

func (*WalletKeyset) UnmarshalJSON

func (wk *WalletKeyset) UnmarshalJSON(data []byte) error

type WalletKeysetTemp

type WalletKeysetTemp struct {
	Id          string
	MintURL     string
	Unit        string
	Active      bool
	PublicKeys  map[uint64][]byte
	Counter     uint32
	InputFeePpk uint
}