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