lbcutil/address.go

387 lines
14 KiB
Go
Raw Normal View History

// Copyright (c) 2013, 2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package btcutil
import (
"bytes"
"encoding/hex"
"errors"
2014-07-03 02:29:48 +02:00
"code.google.com/p/go.crypto/ripemd160"
"github.com/conformal/btcec"
"github.com/conformal/btcnet"
"github.com/conformal/btcwire"
)
var (
// ErrChecksumMismatch describes an error where decoding failed due
// to a bad checksum.
ErrChecksumMismatch = errors.New("checksum mismatch")
// ErrUnknownAddressType describes an error where an address can not
// decoded as a specific address type due to the string encoding
// begining with an identifier byte unknown to any standard or
// registered (via btcnet.Register) network.
ErrUnknownAddressType = errors.New("unknown address type")
// ErrAddressCollision describes an error where an address can not
// be uniquely determined as either a pay-to-pubkey-hash or
// pay-to-script-hash address since the leading identifier is used for
// describing both address kinds, but for different networks. Rather
// than assuming or defaulting to one or the other, this error is
// returned and the caller must decide how to decode the address.
ErrAddressCollision = errors.New("address collision")
)
// encodeAddress returns a human-readable payment address given a ripemd160 hash
// and netID which encodes the bitcoin network and address type. It is used
// in both pay-to-pubkey-hash (P2PKH) and pay-to-script-hash (P2SH) address
// encoding.
func encodeAddress(hash160 []byte, netID byte) string {
// Format is 1 byte for a network and address class (i.e. P2PKH vs
// P2SH), 20 bytes for a RIPEMD160 hash, and 4 bytes of checksum.
b := make([]byte, 0, 1+ripemd160.Size+4)
b = append(b, netID)
b = append(b, hash160...)
cksum := btcwire.DoubleSha256(b)[:4]
b = append(b, cksum...)
return Base58Encode(b)
}
// Address is an interface type for any type of destination a transaction
// output may spend to. This includes pay-to-pubkey (P2PK), pay-to-pubkey-hash
// (P2PKH), and pay-to-script-hash (P2SH). Address is designed to be generic
// enough that other kinds of addresses may be added in the future without
// changing the decoding and encoding API.
type Address interface {
2014-06-13 03:11:24 +02:00
// String returns the string encoding of the transaction output
// destination.
//
// Please note that String differs subtly from EncodeAddress: String
// will return the value as a string without any conversion, while
// EncodeAddress may convert destination types (for example,
// converting pubkeys to P2PKH addresses) before encoding as a
// payment address string.
String() string
// EncodeAddress returns the string encoding of the payment address
// associated with the Address value. See the comment on String
// for how this method differs from String.
EncodeAddress() string
// ScriptAddress returns the raw bytes of the address to be used
// when inserting the address into a txout's script.
ScriptAddress() []byte
// IsForNet returns whether or not the address is associated with the
// passed bitcoin network.
IsForNet(*btcnet.Params) bool
}
// DecodeAddress decodes the string encoding of an address and returns
// the Address if addr is a valid encoding for a known address type.
//
// The bitcoin network the address is associated with is extracted if possible.
// When the address does not encode the network, such as in the case of a raw
// public key, the address will be associated with the passed defaultNet.
func DecodeAddress(addr string, defaultNet *btcnet.Params) (Address, error) {
// Serialized public keys are either 65 bytes (130 hex chars) if
// uncompressed/hybrid or 33 bytes (66 hex chars) if compressed.
if len(addr) == 130 || len(addr) == 66 {
serializedPubKey, err := hex.DecodeString(addr)
if err != nil {
return nil, err
}
return NewAddressPubKey(serializedPubKey, defaultNet)
}
// Switch on decoded length to determine the type.
decoded := Base58Decode(addr)
switch len(decoded) {
case 1 + ripemd160.Size + 4: // P2PKH or P2SH
// Verify hash checksum. Checksum is calculated as the first
// four bytes of double SHA256 of the network byte and hash.
tosum := decoded[:ripemd160.Size+1]
cksum := btcwire.DoubleSha256(tosum)[:4]
if !bytes.Equal(cksum, decoded[len(decoded)-4:]) {
return nil, ErrChecksumMismatch
}
netID := decoded[0]
isP2PKH := btcnet.IsPubKeyHashAddrID(netID)
isP2SH := btcnet.IsScriptHashAddrID(netID)
switch hash160 := decoded[1 : ripemd160.Size+1]; {
case isP2PKH && isP2SH:
return nil, ErrAddressCollision
case isP2PKH:
return newAddressPubKeyHash(hash160, netID)
case isP2SH:
return newAddressScriptHashFromHash(hash160, netID)
default:
return nil, ErrUnknownAddressType
}
default:
return nil, errors.New("decoded address is of unknown size")
}
}
// AddressPubKeyHash is an Address for a pay-to-pubkey-hash (P2PKH)
// transaction.
type AddressPubKeyHash struct {
hash [ripemd160.Size]byte
netID byte
}
// NewAddressPubKeyHash returns a new AddressPubKeyHash. pkHash must
// be 20 bytes.
func NewAddressPubKeyHash(pkHash []byte, net *btcnet.Params) (*AddressPubKeyHash, error) {
return newAddressPubKeyHash(pkHash, net.PubKeyHashAddrID)
}
// newAddressPubKeyHash is the internal API to create a pubkey hash address
// with a known leading identifier byte for a network, rather than looking
// it up through its parameters. This is useful when creating a new address
// structure from a string encoding where the identifer byte is already
// known.
func newAddressPubKeyHash(pkHash []byte, netID byte) (*AddressPubKeyHash, error) {
// Check for a valid pubkey hash length.
if len(pkHash) != ripemd160.Size {
return nil, errors.New("pkHash must be 20 bytes")
}
addr := &AddressPubKeyHash{netID: netID}
copy(addr.hash[:], pkHash)
return addr, nil
}
// EncodeAddress returns the string encoding of a pay-to-pubkey-hash
// address. Part of the Address interface.
func (a *AddressPubKeyHash) EncodeAddress() string {
return encodeAddress(a.hash[:], a.netID)
}
// ScriptAddress returns the bytes to be included in a txout script to pay
// to a pubkey hash. Part of the Address interface.
func (a *AddressPubKeyHash) ScriptAddress() []byte {
return a.hash[:]
}
// IsForNet returns whether or not the pay-to-pubkey-hash address is associated
// with the passed bitcoin network.
func (a *AddressPubKeyHash) IsForNet(net *btcnet.Params) bool {
return a.netID == net.PubKeyHashAddrID
}
// String returns a human-readable string for the pay-to-pubkey-hash address.
// This is equivalent to calling EncodeAddress, but is provided so the type can
// be used as a fmt.Stringer.
func (a *AddressPubKeyHash) String() string {
return a.EncodeAddress()
}
// Hash160 returns the underlying array of the pubkey hash. This can be useful
// when an array is more appropiate than a slice (for example, when used as map
// keys).
func (a *AddressPubKeyHash) Hash160() *[ripemd160.Size]byte {
return &a.hash
}
// AddressScriptHash is an Address for a pay-to-script-hash (P2SH)
// transaction.
type AddressScriptHash struct {
hash [ripemd160.Size]byte
netID byte
}
// NewAddressScriptHash returns a new AddressScriptHash.
func NewAddressScriptHash(serializedScript []byte, net *btcnet.Params) (*AddressScriptHash, error) {
scriptHash := Hash160(serializedScript)
return newAddressScriptHashFromHash(scriptHash, net.ScriptHashAddrID)
}
// NewAddressScriptHashFromHash returns a new AddressScriptHash. scriptHash
// must be 20 bytes.
func NewAddressScriptHashFromHash(scriptHash []byte, net *btcnet.Params) (*AddressScriptHash, error) {
return newAddressScriptHashFromHash(scriptHash, net.ScriptHashAddrID)
}
// newAddressScriptHashFromHash is the internal API to create a script hash
// address with a known leading identifier byte for a network, rather than
// looking it up through its parameters. This is useful when creating a new
// address structure from a string encoding where the identifer byte is already
// known.
func newAddressScriptHashFromHash(scriptHash []byte, netID byte) (*AddressScriptHash, error) {
// Check for a valid script hash length.
if len(scriptHash) != ripemd160.Size {
return nil, errors.New("scriptHash must be 20 bytes")
}
addr := &AddressScriptHash{netID: netID}
copy(addr.hash[:], scriptHash)
return addr, nil
}
// EncodeAddress returns the string encoding of a pay-to-script-hash
// address. Part of the Address interface.
func (a *AddressScriptHash) EncodeAddress() string {
return encodeAddress(a.hash[:], a.netID)
}
// ScriptAddress returns the bytes to be included in a txout script to pay
// to a script hash. Part of the Address interface.
func (a *AddressScriptHash) ScriptAddress() []byte {
return a.hash[:]
}
// IsForNet returns whether or not the pay-to-script-hash address is associated
// with the passed bitcoin network.
func (a *AddressScriptHash) IsForNet(net *btcnet.Params) bool {
return a.netID == net.ScriptHashAddrID
}
// String returns a human-readable string for the pay-to-script-hash address.
// This is equivalent to calling EncodeAddress, but is provided so the type can
// be used as a fmt.Stringer.
func (a *AddressScriptHash) String() string {
return a.EncodeAddress()
}
// Hash160 returns the underlying array of the script hash. This can be useful
// when an array is more appropiate than a slice (for example, when used as map
// keys).
func (a *AddressScriptHash) Hash160() *[ripemd160.Size]byte {
return &a.hash
}
// PubKeyFormat describes what format to use for a pay-to-pubkey address.
type PubKeyFormat int
const (
// PKFUncompressed indicates the pay-to-pubkey address format is an
// uncompressed public key.
PKFUncompressed PubKeyFormat = iota
// PKFCompressed indicates the pay-to-pubkey address format is a
// compressed public key.
PKFCompressed
// PKFHybrid indicates the pay-to-pubkey address format is a hybrid
// public key.
PKFHybrid
)
// AddressPubKey is an Address for a pay-to-pubkey transaction.
type AddressPubKey struct {
pubKeyFormat PubKeyFormat
pubKey *btcec.PublicKey
pubKeyHashID byte
}
// NewAddressPubKey returns a new AddressPubKey which represents a pay-to-pubkey
// address. The serializedPubKey parameter must be a valid pubkey and can be
// uncompressed, compressed, or hybrid.
func NewAddressPubKey(serializedPubKey []byte, net *btcnet.Params) (*AddressPubKey, error) {
pubKey, err := btcec.ParsePubKey(serializedPubKey, btcec.S256())
if err != nil {
return nil, err
}
// Set the format of the pubkey. This probably should be returned
// from btcec, but do it here to avoid API churn. We already know the
// pubkey is valid since it parsed above, so it's safe to simply examine
// the leading byte to get the format.
pkFormat := PKFUncompressed
switch serializedPubKey[0] {
case 0x02, 0x03:
pkFormat = PKFCompressed
case 0x06, 0x07:
pkFormat = PKFHybrid
}
return &AddressPubKey{
pubKeyFormat: pkFormat,
pubKey: pubKey,
pubKeyHashID: net.PubKeyHashAddrID,
}, nil
}
// serialize returns the serialization of the public key according to the
// format associated with the address.
func (a *AddressPubKey) serialize() []byte {
switch a.pubKeyFormat {
default:
fallthrough
case PKFUncompressed:
return a.pubKey.SerializeUncompressed()
case PKFCompressed:
return a.pubKey.SerializeCompressed()
case PKFHybrid:
return a.pubKey.SerializeHybrid()
}
}
// EncodeAddress returns the string encoding of the public key as a
// pay-to-pubkey-hash. Note that the public key format (uncompressed,
// compressed, etc) will change the resulting address. This is expected since
// pay-to-pubkey-hash is a hash of the serialized public key which obviously
// differs with the format. At the time of this writing, most Bitcoin addresses
// are pay-to-pubkey-hash constructed from the uncompressed public key.
//
// Part of the Address interface.
func (a *AddressPubKey) EncodeAddress() string {
return encodeAddress(Hash160(a.serialize()), a.pubKeyHashID)
}
// ScriptAddress returns the bytes to be included in a txout script to pay
// to a public key. Setting the public key format will affect the output of
// this function accordingly. Part of the Address interface.
func (a *AddressPubKey) ScriptAddress() []byte {
return a.serialize()
}
// IsForNet returns whether or not the pay-to-pubkey address is associated
// with the passed bitcoin network.
func (a *AddressPubKey) IsForNet(net *btcnet.Params) bool {
return a.pubKeyHashID == net.PubKeyHashAddrID
}
// String returns the hex-encoded human-readable string for the pay-to-pubkey
// address. This is not the same as calling EncodeAddress.
func (a *AddressPubKey) String() string {
return hex.EncodeToString(a.serialize())
}
2014-04-12 19:02:54 +02:00
// Format returns the format (uncompressed, compressed, etc) of the
// pay-to-pubkey address.
func (a *AddressPubKey) Format() PubKeyFormat {
return a.pubKeyFormat
}
// SetFormat sets the format (uncompressed, compressed, etc) of the
// pay-to-pubkey address.
func (a *AddressPubKey) SetFormat(pkFormat PubKeyFormat) {
a.pubKeyFormat = pkFormat
}
// AddressPubKeyHash returns the pay-to-pubkey address converted to a
// pay-to-pubkey-hash address. Note that the public key format (uncompressed,
// compressed, etc) will change the resulting address. This is expected since
// pay-to-pubkey-hash is a hash of the serialized public key which obviously
// differs with the format. At the time of this writing, most Bitcoin addresses
// are pay-to-pubkey-hash constructed from the uncompressed public key.
func (a *AddressPubKey) AddressPubKeyHash() *AddressPubKeyHash {
addr := &AddressPubKeyHash{netID: a.pubKeyHashID}
copy(addr.hash[:], Hash160(a.serialize()))
return addr
}
// PubKey returns the underlying public key for the address.
func (a *AddressPubKey) PubKey() *btcec.PublicKey {
return a.pubKey
}