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package ed25519
import (
"bytes"
"crypto/subtle"
"fmt"
"io"
"github.com/tendermint/ed25519"
"github.com/tendermint/ed25519/extra25519"
amino "github.com/tendermint/go-amino"
"github.com/tendermint/tendermint/crypto"
"github.com/tendermint/tendermint/crypto/tmhash"
)
//-------------------------------------
var _ crypto.PrivKey = PrivKeyEd25519{}
const (
Ed25519PrivKeyAminoRoute = "tendermint/PrivKeyEd25519"
Ed25519PubKeyAminoRoute = "tendermint/PubKeyEd25519"
// Size of an Edwards25519 signature. Namely the size of a compressed
// Edwards25519 point, and a field element. Both of which are 32 bytes.
SignatureEd25519Size = 64
)
var cdc = amino.NewCodec()
func init() {
cdc.RegisterInterface((*crypto.PubKey)(nil), nil)
cdc.RegisterConcrete(PubKeyEd25519{},
Ed25519PubKeyAminoRoute, nil)
cdc.RegisterInterface((*crypto.PrivKey)(nil), nil)
cdc.RegisterConcrete(PrivKeyEd25519{},
Ed25519PrivKeyAminoRoute, nil)
}
// PrivKeyEd25519 implements crypto.PrivKey.
type PrivKeyEd25519 [64]byte
// Bytes marshals the privkey using amino encoding.
func (privKey PrivKeyEd25519) Bytes() []byte {
return cdc.MustMarshalBinaryBare(privKey)
}
// Sign produces a signature on the provided message.
func (privKey PrivKeyEd25519) Sign(msg []byte) ([]byte, error) {
privKeyBytes := [64]byte(privKey)
signatureBytes := ed25519.Sign(&privKeyBytes, msg)
return signatureBytes[:], nil
}
// PubKey gets the corresponding public key from the private key.
func (privKey PrivKeyEd25519) PubKey() crypto.PubKey {
privKeyBytes := [64]byte(privKey)
initialized := false
// If the latter 32 bytes of the privkey are all zero, compute the pubkey
// otherwise privkey is initialized and we can use the cached value inside
// of the private key.
for _, v := range privKeyBytes[32:] {
if v != 0 {
initialized = true
break
}
}
if initialized {
var pubkeyBytes [PubKeyEd25519Size]byte
copy(pubkeyBytes[:], privKeyBytes[32:])
return PubKeyEd25519(pubkeyBytes)
}
pubBytes := *ed25519.MakePublicKey(&privKeyBytes)
return PubKeyEd25519(pubBytes)
}
// Equals - you probably don't need to use this.
// Runs in constant time based on length of the keys.
func (privKey PrivKeyEd25519) Equals(other crypto.PrivKey) bool {
if otherEd, ok := other.(PrivKeyEd25519); ok {
return subtle.ConstantTimeCompare(privKey[:], otherEd[:]) == 1
} else {
return false
}
}
// ToCurve25519 takes a private key and returns its representation on
// Curve25519. Curve25519 is birationally equivalent to Edwards25519,
// which Ed25519 uses internally. This method is intended for use in
// an X25519 Diffie Hellman key exchange.
func (privKey PrivKeyEd25519) ToCurve25519() *[PubKeyEd25519Size]byte {
keyCurve25519 := new([32]byte)
privKeyBytes := [64]byte(privKey)
extra25519.PrivateKeyToCurve25519(keyCurve25519, &privKeyBytes)
return keyCurve25519
}
// GenPrivKey generates a new ed25519 private key.
// It uses OS randomness in conjunction with the current global random seed
// in tendermint/libs/common to generate the private key.
func GenPrivKey() PrivKeyEd25519 {
return genPrivKey(crypto.CReader())
}
// genPrivKey generates a new ed25519 private key using the provided reader.
func genPrivKey(rand io.Reader) PrivKeyEd25519 {
privKey := new([64]byte)
_, err := io.ReadFull(rand, privKey[:32])
if err != nil {
panic(err)
}
// ed25519.MakePublicKey(privKey) alters the last 32 bytes of privKey.
// It places the pubkey in the last 32 bytes of privKey, and returns the
// public key.
ed25519.MakePublicKey(privKey)
return PrivKeyEd25519(*privKey)
}
// GenPrivKeyFromSecret hashes the secret with SHA2, and uses
// that 32 byte output to create the private key.
// NOTE: secret should be the output of a KDF like bcrypt,
// if it's derived from user input.
func GenPrivKeyFromSecret(secret []byte) PrivKeyEd25519 {
privKey32 := crypto.Sha256(secret) // Not Ripemd160 because we want 32 bytes.
privKey := new([64]byte)
copy(privKey[:32], privKey32)
// ed25519.MakePublicKey(privKey) alters the last 32 bytes of privKey.
// It places the pubkey in the last 32 bytes of privKey, and returns the
// public key.
ed25519.MakePublicKey(privKey)
return PrivKeyEd25519(*privKey)
}
//-------------------------------------
var _ crypto.PubKey = PubKeyEd25519{}
// PubKeyEd25519Size is the number of bytes in an Ed25519 signature.
const PubKeyEd25519Size = 32
// PubKeyEd25519 implements crypto.PubKey for the Ed25519 signature scheme.
type PubKeyEd25519 [PubKeyEd25519Size]byte
// Address is the SHA256-20 of the raw pubkey bytes.
func (pubKey PubKeyEd25519) Address() crypto.Address {
return crypto.Address(tmhash.Sum(pubKey[:]))
}
// Bytes marshals the PubKey using amino encoding.
func (pubKey PubKeyEd25519) Bytes() []byte {
bz, err := cdc.MarshalBinaryBare(pubKey)
if err != nil {
panic(err)
}
return bz
}
func (pubKey PubKeyEd25519) VerifyBytes(msg []byte, sig_ []byte) bool {
// make sure we use the same algorithm to sign
if len(sig_) != SignatureEd25519Size {
return false
}
sig := new([SignatureEd25519Size]byte)
copy(sig[:], sig_)
pubKeyBytes := [PubKeyEd25519Size]byte(pubKey)
return ed25519.Verify(&pubKeyBytes, msg, sig)
}
// ToCurve25519 takes a public key and returns its representation on
// Curve25519. Curve25519 is birationally equivalent to Edwards25519,
// which Ed25519 uses internally. This method is intended for use in
// an X25519 Diffie Hellman key exchange.
//
// If there is an error, then this function returns nil.
func (pubKey PubKeyEd25519) ToCurve25519() *[PubKeyEd25519Size]byte {
keyCurve25519, pubKeyBytes := new([PubKeyEd25519Size]byte), [PubKeyEd25519Size]byte(pubKey)
ok := extra25519.PublicKeyToCurve25519(keyCurve25519, &pubKeyBytes)
if !ok {
return nil
}
return keyCurve25519
}
func (pubKey PubKeyEd25519) String() string {
return fmt.Sprintf("PubKeyEd25519{%X}", pubKey[:])
}
// nolint: golint
func (pubKey PubKeyEd25519) Equals(other crypto.PubKey) bool {
if otherEd, ok := other.(PubKeyEd25519); ok {
return bytes.Equal(pubKey[:], otherEd[:])
} else {
return false
}
}