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204 lines
5.4 KiB
204 lines
5.4 KiB
package ed25519
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import (
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"bytes"
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"crypto/ed25519"
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"crypto/subtle"
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"errors"
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"fmt"
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"io"
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"github.com/hdevalence/ed25519consensus"
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"github.com/tendermint/tendermint/crypto"
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"github.com/tendermint/tendermint/crypto/tmhash"
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tmjson "github.com/tendermint/tendermint/libs/json"
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)
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//-------------------------------------
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var _ crypto.PrivKey = PrivKey{}
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const (
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PrivKeyName = "tendermint/PrivKeyEd25519"
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PubKeyName = "tendermint/PubKeyEd25519"
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// PubKeySize is is the size, in bytes, of public keys as used in this package.
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PubKeySize = 32
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// PrivateKeySize is the size, in bytes, of private keys as used in this package.
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PrivateKeySize = 64
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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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// SeedSize is the size, in bytes, of private key seeds. These are the
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// private key representations used by RFC 8032.
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SeedSize = 32
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KeyType = "ed25519"
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)
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func init() {
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tmjson.RegisterType(PubKey{}, PubKeyName)
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tmjson.RegisterType(PrivKey{}, PrivKeyName)
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}
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// PrivKey implements crypto.PrivKey.
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type PrivKey []byte
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// Bytes returns the privkey byte format.
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func (privKey PrivKey) Bytes() []byte {
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return []byte(privKey)
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}
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// Sign produces a signature on the provided message.
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// This assumes the privkey is wellformed in the golang format.
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// The first 32 bytes should be random,
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// corresponding to the normal ed25519 private key.
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// The latter 32 bytes should be the compressed public key.
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// If these conditions aren't met, Sign will panic or produce an
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// incorrect signature.
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func (privKey PrivKey) Sign(msg []byte) ([]byte, error) {
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signatureBytes := ed25519.Sign(ed25519.PrivateKey(privKey), 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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//
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// Panics if the private key is not initialized.
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func (privKey PrivKey) PubKey() crypto.PubKey {
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// If the latter 32 bytes of the privkey are all zero, privkey is not
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// initialized.
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initialized := false
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for _, v := range privKey[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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panic("Expected ed25519 PrivKey to include concatenated pubkey bytes")
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}
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pubkeyBytes := make([]byte, PubKeySize)
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copy(pubkeyBytes, privKey[32:])
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return PubKey(pubkeyBytes)
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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 PrivKey) Equals(other crypto.PrivKey) bool {
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if otherEd, ok := other.(PrivKey); ok {
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return subtle.ConstantTimeCompare(privKey[:], otherEd[:]) == 1
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}
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return false
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}
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func (privKey PrivKey) Type() string {
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return KeyType
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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() PrivKey {
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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) PrivKey {
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seed := make([]byte, SeedSize)
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_, err := io.ReadFull(rand, seed)
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if err != nil {
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panic(err)
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}
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return PrivKey(ed25519.NewKeyFromSeed(seed))
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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) PrivKey {
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seed := crypto.Sha256(secret) // Not Ripemd160 because we want 32 bytes.
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return PrivKey(ed25519.NewKeyFromSeed(seed))
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}
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//-------------------------------------
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var _ crypto.PubKey = PubKey{}
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// PubKeyEd25519 implements crypto.PubKey for the Ed25519 signature scheme.
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type PubKey []byte
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// Address is the SHA256-20 of the raw pubkey bytes.
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func (pubKey PubKey) Address() crypto.Address {
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if len(pubKey) != PubKeySize {
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panic("pubkey is incorrect size")
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}
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return crypto.Address(tmhash.SumTruncated(pubKey))
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}
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// Bytes returns the PubKey byte format.
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func (pubKey PubKey) Bytes() []byte {
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return []byte(pubKey)
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}
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func (pubKey PubKey) VerifySignature(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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return ed25519consensus.Verify(ed25519.PublicKey(pubKey), msg, sig)
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}
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func (pubKey PubKey) String() string {
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return fmt.Sprintf("PubKeyEd25519{%X}", []byte(pubKey))
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}
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func (pubKey PubKey) Type() string {
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return KeyType
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}
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func (pubKey PubKey) Equals(other crypto.PubKey) bool {
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if otherEd, ok := other.(PubKey); ok {
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return bytes.Equal(pubKey[:], otherEd[:])
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}
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return false
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}
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var _ crypto.BatchVerifier = &BatchVerifier{}
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// BatchVerifier implements batch verification for ed25519.
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// https://github.com/hdevalence/ed25519consensus is used for batch verification
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type BatchVerifier struct {
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ed25519consensus.BatchVerifier
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}
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func NewBatchVerifier() crypto.BatchVerifier {
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return &BatchVerifier{ed25519consensus.NewBatchVerifier()}
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}
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func (b *BatchVerifier) Add(key crypto.PubKey, msg, signature []byte) error {
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if l := len(key.Bytes()); l != PubKeySize {
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return fmt.Errorf("pubkey size is incorrect; expected: %d, got %d", PubKeySize, l)
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}
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// check that the signature is the correct length & the last byte is set correctly
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if len(signature) != SignatureSize || signature[63]&224 != 0 {
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return errors.New("invalid signature")
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}
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b.BatchVerifier.Add(ed25519.PublicKey(key.Bytes()), msg, signature)
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return nil
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}
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func (b *BatchVerifier) Verify() bool {
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return b.BatchVerifier.Verify()
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}
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