0fb3e7eabd
This updates VerifyMessage to use the stdaddr package for addresses instead of the local Address type in preparation for its removal.
98 lines
3.2 KiB
Go
98 lines
3.2 KiB
Go
// Copyright (c) 2013, 2014 The btcsuite developers
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// Copyright (c) 2015-2021 The Decred developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package dcrutil
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import (
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"bytes"
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"encoding/base64"
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"fmt"
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"github.com/decred/dcrd/chaincfg/chainhash"
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"github.com/decred/dcrd/dcrec/secp256k1/v4/ecdsa"
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"github.com/decred/dcrd/txscript/v4/stdaddr"
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"github.com/decred/dcrd/wire"
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)
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// AddressParams defines an interface that is used to provide the parameters
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// required when encoding and decoding addresses. These values are typically
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// well-defined and unique per network.
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type AddressParams interface {
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// AddrIDPubKeyV0 returns the magic prefix bytes for version 0 pay-to-pubkey
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// addresses.
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AddrIDPubKeyV0() [2]byte
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// AddrIDPubKeyHashECDSAV0 returns the magic prefix bytes for version 0
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// pay-to-pubkey-hash addresses where the underlying pubkey is secp256k1 and
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// the signature algorithm is ECDSA.
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AddrIDPubKeyHashECDSAV0() [2]byte
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// AddrIDPubKeyHashEd25519V0 returns the magic prefix bytes for version 0
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// pay-to-pubkey-hash addresses where the underlying pubkey and signature
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// algorithm are Ed25519.
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AddrIDPubKeyHashEd25519V0() [2]byte
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// AddrIDPubKeyHashSchnorrV0 returns the magic prefix bytes for version 0
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// pay-to-pubkey-hash addresses where the underlying pubkey is secp256k1 and
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// the signature algorithm is Schnorr.
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AddrIDPubKeyHashSchnorrV0() [2]byte
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// AddrIDScriptHashV0 returns the magic prefix bytes for version 0
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// pay-to-script-hash addresses.
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AddrIDScriptHashV0() [2]byte
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}
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// VerifyMessage verifies that signature is a valid signature of message and was created
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// using the secp256k1 private key for address.
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func VerifyMessage(address string, signature string, message string, params AddressParams) error {
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// Decode the provided address. This also ensures the network encoded with
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// the address matches the network the server is currently on.
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addr, err := stdaddr.DecodeAddress(address, params)
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if err != nil {
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return err
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}
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// Only P2PKH addresses are valid for signing.
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if _, ok := addr.(*stdaddr.AddressPubKeyHashEcdsaSecp256k1V0); !ok {
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return fmt.Errorf("address is not a pay-to-pubkey-hash address")
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}
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// Decode base64 signature.
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sig, err := base64.StdEncoding.DecodeString(signature)
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if err != nil {
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return fmt.Errorf("malformed base64 encoding: %v", err)
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}
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// Validate the signature - this just shows that it was valid for any pubkey
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// at all. Whether the pubkey matches is checked below.
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var buf bytes.Buffer
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wire.WriteVarString(&buf, 0, "Decred Signed Message:\n")
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wire.WriteVarString(&buf, 0, message)
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expectedMessageHash := chainhash.HashB(buf.Bytes())
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pk, wasCompressed, err := ecdsa.RecoverCompact(sig, expectedMessageHash)
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if err != nil {
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return err
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}
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// Reconstruct the address from the recovered pubkey.
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var pkHash []byte
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if wasCompressed {
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pkHash = stdaddr.Hash160(pk.SerializeCompressed())
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} else {
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pkHash = stdaddr.Hash160(pk.SerializeUncompressed())
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}
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recAddr, err := stdaddr.NewAddressPubKeyHashEcdsaSecp256k1V0(pkHash, params)
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if err != nil {
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return err
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}
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// Check whether addresses match.
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if recAddr.String() != addr.String() {
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return fmt.Errorf("message not signed by address")
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}
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return nil
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}
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