You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
174 lines
4.8 KiB
174 lines
4.8 KiB
package secp256k1
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/sha256"
|
|
"crypto/subtle"
|
|
"fmt"
|
|
"io"
|
|
"math/big"
|
|
|
|
secp256k1 "github.com/btcsuite/btcd/btcec"
|
|
"github.com/tendermint/tendermint/crypto"
|
|
tmjson "github.com/tendermint/tendermint/libs/json"
|
|
|
|
// necessary for Bitcoin address format
|
|
"golang.org/x/crypto/ripemd160" // nolint
|
|
)
|
|
|
|
//-------------------------------------
|
|
const (
|
|
PrivKeyName = "tendermint/PrivKeySecp256k1"
|
|
PubKeyName = "tendermint/PubKeySecp256k1"
|
|
|
|
KeyType = "secp256k1"
|
|
PrivKeySize = 32
|
|
)
|
|
|
|
func init() {
|
|
tmjson.RegisterType(PubKey{}, PubKeyName)
|
|
tmjson.RegisterType(PrivKey{}, PrivKeyName)
|
|
}
|
|
|
|
var _ crypto.PrivKey = PrivKey{}
|
|
|
|
// PrivKey implements PrivKey.
|
|
type PrivKey []byte
|
|
|
|
// Bytes marshalls the private key using amino encoding.
|
|
func (privKey PrivKey) Bytes() []byte {
|
|
return []byte(privKey)
|
|
}
|
|
|
|
// PubKey performs the point-scalar multiplication from the privKey on the
|
|
// generator point to get the pubkey.
|
|
func (privKey PrivKey) PubKey() crypto.PubKey {
|
|
_, pubkeyObject := secp256k1.PrivKeyFromBytes(secp256k1.S256(), privKey)
|
|
|
|
pk := pubkeyObject.SerializeCompressed()
|
|
|
|
return PubKey(pk)
|
|
}
|
|
|
|
// Equals - you probably don't need to use this.
|
|
// Runs in constant time based on length of the keys.
|
|
func (privKey PrivKey) Equals(other crypto.PrivKey) bool {
|
|
if otherSecp, ok := other.(PrivKey); ok {
|
|
return subtle.ConstantTimeCompare(privKey[:], otherSecp[:]) == 1
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (privKey PrivKey) Type() string {
|
|
return KeyType
|
|
}
|
|
|
|
// GenPrivKey generates a new ECDSA private key on curve secp256k1 private key.
|
|
// It uses OS randomness to generate the private key.
|
|
func GenPrivKey() PrivKey {
|
|
return genPrivKey(crypto.CReader())
|
|
}
|
|
|
|
// genPrivKey generates a new secp256k1 private key using the provided reader.
|
|
func genPrivKey(rand io.Reader) PrivKey {
|
|
var privKeyBytes [PrivKeySize]byte
|
|
d := new(big.Int)
|
|
|
|
for {
|
|
privKeyBytes = [PrivKeySize]byte{}
|
|
_, err := io.ReadFull(rand, privKeyBytes[:])
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
d.SetBytes(privKeyBytes[:])
|
|
// break if we found a valid point (i.e. > 0 and < N == curverOrder)
|
|
isValidFieldElement := 0 < d.Sign() && d.Cmp(secp256k1.S256().N) < 0
|
|
if isValidFieldElement {
|
|
break
|
|
}
|
|
}
|
|
|
|
return PrivKey(privKeyBytes[:])
|
|
}
|
|
|
|
var one = new(big.Int).SetInt64(1)
|
|
|
|
// GenPrivKeySecp256k1 hashes the secret with SHA2, and uses
|
|
// that 32 byte output to create the private key.
|
|
//
|
|
// It makes sure the private key is a valid field element by setting:
|
|
//
|
|
// c = sha256(secret)
|
|
// k = (c mod (n − 1)) + 1, where n = curve order.
|
|
//
|
|
// NOTE: secret should be the output of a KDF like bcrypt,
|
|
// if it's derived from user input.
|
|
func GenPrivKeySecp256k1(secret []byte) PrivKey {
|
|
secHash := sha256.Sum256(secret)
|
|
// to guarantee that we have a valid field element, we use the approach of:
|
|
// "Suite B Implementer’s Guide to FIPS 186-3", A.2.1
|
|
// https://apps.nsa.gov/iaarchive/library/ia-guidance/ia-solutions-for-classified/algorithm-guidance/suite-b-implementers-guide-to-fips-186-3-ecdsa.cfm
|
|
// see also https://github.com/golang/go/blob/0380c9ad38843d523d9c9804fe300cb7edd7cd3c/src/crypto/ecdsa/ecdsa.go#L89-L101
|
|
fe := new(big.Int).SetBytes(secHash[:])
|
|
n := new(big.Int).Sub(secp256k1.S256().N, one)
|
|
fe.Mod(fe, n)
|
|
fe.Add(fe, one)
|
|
|
|
feB := fe.Bytes()
|
|
privKey32 := make([]byte, PrivKeySize)
|
|
// copy feB over to fixed 32 byte privKey32 and pad (if necessary)
|
|
copy(privKey32[32-len(feB):32], feB)
|
|
|
|
return PrivKey(privKey32)
|
|
}
|
|
|
|
//-------------------------------------
|
|
|
|
var _ crypto.PubKey = PubKey{}
|
|
|
|
// PubKeySize is comprised of 32 bytes for one field element
|
|
// (the x-coordinate), plus one byte for the parity of the y-coordinate.
|
|
const PubKeySize = 33
|
|
|
|
// PubKey implements crypto.PubKey.
|
|
// It is the compressed form of the pubkey. The first byte depends is a 0x02 byte
|
|
// if the y-coordinate is the lexicographically largest of the two associated with
|
|
// the x-coordinate. Otherwise the first byte is a 0x03.
|
|
// This prefix is followed with the x-coordinate.
|
|
type PubKey []byte
|
|
|
|
// Address returns a Bitcoin style addresses: RIPEMD160(SHA256(pubkey))
|
|
func (pubKey PubKey) Address() crypto.Address {
|
|
if len(pubKey) != PubKeySize {
|
|
panic("length of pubkey is incorrect")
|
|
}
|
|
hasherSHA256 := sha256.New()
|
|
_, _ = hasherSHA256.Write(pubKey) // does not error
|
|
sha := hasherSHA256.Sum(nil)
|
|
|
|
hasherRIPEMD160 := ripemd160.New()
|
|
_, _ = hasherRIPEMD160.Write(sha) // does not error
|
|
|
|
return crypto.Address(hasherRIPEMD160.Sum(nil))
|
|
}
|
|
|
|
// Bytes returns the pubkey marshaled with amino encoding.
|
|
func (pubKey PubKey) Bytes() []byte {
|
|
return []byte(pubKey)
|
|
}
|
|
|
|
func (pubKey PubKey) String() string {
|
|
return fmt.Sprintf("PubKeySecp256k1{%X}", []byte(pubKey))
|
|
}
|
|
|
|
func (pubKey PubKey) Equals(other crypto.PubKey) bool {
|
|
if otherSecp, ok := other.(PubKey); ok {
|
|
return bytes.Equal(pubKey[:], otherSecp[:])
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (pubKey PubKey) Type() string {
|
|
return KeyType
|
|
}
|