115 lines
3.0 KiB
Go
115 lines
3.0 KiB
Go
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// Copyright 2018 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package enr
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import (
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"crypto/ecdsa"
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"fmt"
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"sync"
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"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/crypto/sha3"
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"github.com/ethereum/go-ethereum/rlp"
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)
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// Registry of known identity schemes.
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var schemes sync.Map
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// An IdentityScheme is capable of verifying record signatures and
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// deriving node addresses.
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type IdentityScheme interface {
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Verify(r *Record, sig []byte) error
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NodeAddr(r *Record) []byte
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}
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// RegisterIdentityScheme adds an identity scheme to the global registry.
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func RegisterIdentityScheme(name string, scheme IdentityScheme) {
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if _, loaded := schemes.LoadOrStore(name, scheme); loaded {
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panic("identity scheme " + name + " already registered")
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}
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}
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// FindIdentityScheme resolves name to an identity scheme in the global registry.
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func FindIdentityScheme(name string) IdentityScheme {
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s, ok := schemes.Load(name)
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if !ok {
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return nil
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}
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return s.(IdentityScheme)
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}
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// v4ID is the "v4" identity scheme.
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type v4ID struct{}
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func init() {
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RegisterIdentityScheme("v4", v4ID{})
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}
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// SignV4 signs a record using the v4 scheme.
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func SignV4(r *Record, privkey *ecdsa.PrivateKey) error {
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// Copy r to avoid modifying it if signing fails.
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cpy := *r
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cpy.Set(ID("v4"))
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cpy.Set(Secp256k1(privkey.PublicKey))
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h := sha3.NewKeccak256()
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rlp.Encode(h, cpy.AppendElements(nil))
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sig, err := crypto.Sign(h.Sum(nil), privkey)
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if err != nil {
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return err
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}
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sig = sig[:len(sig)-1] // remove v
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if err = cpy.SetSig("v4", sig); err == nil {
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*r = cpy
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}
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return err
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}
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// s256raw is an unparsed secp256k1 public key entry.
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type s256raw []byte
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func (s256raw) ENRKey() string { return "secp256k1" }
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func (v4ID) Verify(r *Record, sig []byte) error {
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var entry s256raw
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if err := r.Load(&entry); err != nil {
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return err
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} else if len(entry) != 33 {
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return fmt.Errorf("invalid public key")
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}
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h := sha3.NewKeccak256()
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rlp.Encode(h, r.AppendElements(nil))
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if !crypto.VerifySignature(entry, h.Sum(nil), sig) {
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return errInvalidSig
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}
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return nil
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}
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func (v4ID) NodeAddr(r *Record) []byte {
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var pubkey Secp256k1
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err := r.Load(&pubkey)
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if err != nil {
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return nil
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}
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buf := make([]byte, 64)
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math.ReadBits(pubkey.X, buf[:32])
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math.ReadBits(pubkey.Y, buf[32:])
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return crypto.Keccak256(buf)
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}
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