add Bech32-encoded address support

introduce CBase58Address and CBech32Address
make CBitcoinAddress a wrapper that returns CBase58Address or
CBech32Address depending on input data

introduce to_redeemScript() method,
because for P2WPKHBitcoinAddress redeem script is not the same
as scriptPubKey.

unfortunately, for P2WSHBitcoinAddress to_redeemScript() cannot
be implemented, as we need all pubkeys for that,
and not only the hash.

Author: dgpv

bitcoin/bech32.py

@@ -73,3 +73,9 @@ def __str__(self):
 
     def __repr__(self):
         return '%s(%r)' % (self.__class__.__name__, str(self))
+
+__all__ = (
+    'Bech32Error',
+    'Bech32ChecksumError',
+    'CBech32Data',
+)

bitcoin/tests/test_bech32.py

@@ -29,6 +29,7 @@
 
 from bitcoin.core.script import CScript, OP_0, OP_1, OP_16
 from bitcoin.bech32 import *
+from bitcoin.segwit_addr import encode, decode
 
 
 def load_test_vectors(name):

bitcoin/tests/test_segwit.py

@@ -36,8 +36,8 @@ def test_p2wpkh_signaturehash(self):
         scriptpubkey  = CScript(x('00141d0f172a0ecb48aee1be1f2687d2963ae33f71a1'))
         value         = int(6*COIN)
 
-        address = CBitcoinAddress.from_scriptPubKey(scriptpubkey)
-        self.assertEqual(SignatureHash(address.to_scriptPubKey(), CTransaction.deserialize(unsigned_tx),
+        address = CBech32BitcoinAddress.from_scriptPubKey(scriptpubkey)
+        self.assertEqual(SignatureHash(address.to_redeemScript(), CTransaction.deserialize(unsigned_tx),
                 1, SIGHASH_ALL, value, SIGVERSION_WITNESS_V0),
             x('c37af31116d1b27caf68aae9e3ac82f1477929014d5b917657d0eb49478cb670'))
 
@@ -47,8 +47,8 @@ def test_p2sh_p2wpkh_signaturehash(self):
         redeemscript  = CScript(x('001479091972186c449eb1ded22b78e40d009bdf0089'))
         value         = int(10*COIN)
 
-        address = CBitcoinAddress.from_scriptPubKey(redeemscript)
-        self.assertEqual(SignatureHash(address.to_scriptPubKey(), CTransaction.deserialize(unsigned_tx),
+        address = CBase58BitcoinAddress.from_scriptPubKey(redeemscript)
+        self.assertEqual(SignatureHash(address.to_redeemScript(), CTransaction.deserialize(unsigned_tx),
                 0, SIGHASH_ALL, value, SIGVERSION_WITNESS_V0),
             x('64f3b0f4dd2bb3aa1ce8566d220cc74dda9df97d8490cc81d89d735c92e59fb6'))
 

bitcoin/wallet.py

@@ -25,19 +25,93 @@
 
 import bitcoin
 import bitcoin.base58
+import bitcoin.bech32
 import bitcoin.core
 import bitcoin.core.key
 import bitcoin.core.script as script
 
-class CBitcoinAddressError(bitcoin.base58.Base58Error):
+
+class CBitcoinAddress(object):
+
+    def __new__(cls, s):
+        try:
+            return CBech32BitcoinAddress(s)
+        except bitcoin.bech32.Bech32Error:
+            pass
+
+        try:
+            return CBase58BitcoinAddress(s)
+        except bitcoin.base58.Base58Error:
+            pass
+
+        raise CBitcoinAddressError('Unrecognized encoding for bitcoin address')
+
+    @classmethod
+    def from_scriptPubKey(cls, scriptPubKey):
+        """Convert a scriptPubKey to a subclass of CBitcoinAddress"""
+        try:
+            return CBech32BitcoinAddress.from_scriptPubKey(scriptPubKey)
+        except CBitcoinAddressError:
+            pass
+
+        try:
+            return CBase58BitcoinAddress.from_scriptPubKey(scriptPubKey)
+        except CBitcoinAddressError:
+            pass
+
+        raise CBitcoinAddressError('scriptPubKey is not in a recognized address format')
+
+
+class CBitcoinAddressError(Exception):
     """Raised when an invalid Bitcoin address is encountered"""
 
-class CBitcoinAddress(bitcoin.base58.CBase58Data):
-    """A Bitcoin address"""
+
+class CBech32BitcoinAddress(bitcoin.bech32.CBech32Data, CBitcoinAddress):
+    """A Bech32-encoded Bitcoin address"""
+
+    @classmethod
+    def from_bytes(cls, witver, witprog):
+
+        assert(witver == 0)
+
+        self = super(CBech32BitcoinAddress, cls).from_bytes(witver, witprog)
+
+        if len(self) == 32:
+            self.__class__ = P2WSHBitcoinAddress
+        elif len(self) == 20:
+            self.__class__ = P2WPKHBitcoinAddress
+        else:
+           raise CBitcoinAddressError('witness program does not match any known segwit address format')
+
+        return self
+
+    @classmethod
+    def from_scriptPubKey(cls, scriptPubKey):
+        """Convert a scriptPubKey to a CBech32BitcoinAddress
+
+        Returns a CBech32BitcoinAddress subclass, either P2WSHBitcoinAddress or
+        P2WPKHBitcoinAddress. If the scriptPubKey is not recognized
+        CBitcoinAddressError will be raised.
+        """
+        try:
+            return P2WSHBitcoinAddress.from_scriptPubKey(scriptPubKey)
+        except CBitcoinAddressError:
+            pass
+
+        try:
+            return P2WPKHBitcoinAddress.from_scriptPubKey(scriptPubKey)
+        except CBitcoinAddressError:
+            pass
+
+        raise CBitcoinAddressError('scriptPubKey not a valid bech32-encoded address')
+
+
+class CBase58BitcoinAddress(bitcoin.base58.CBase58Data, CBitcoinAddress):
+    """A Base58-encoded Bitcoin address"""
 
     @classmethod
     def from_bytes(cls, data, nVersion):
-        self = super(CBitcoinAddress, cls).from_bytes(data, nVersion)
+        self = super(CBase58BitcoinAddress, cls).from_bytes(data, nVersion)
 
         if nVersion == bitcoin.params.BASE58_PREFIXES['SCRIPT_ADDR']:
             self.__class__ = P2SHBitcoinAddress
@@ -68,13 +142,10 @@ def from_scriptPubKey(cls, scriptPubKey):
         except CBitcoinAddressError:
             pass
 
-        raise CBitcoinAddressError('scriptPubKey not a valid address')
+        raise CBitcoinAddressError('scriptPubKey not a valid base58-encoded address')
 
-    def to_scriptPubKey(self):
-        """Convert an address to a scriptPubKey"""
-        raise NotImplementedError
 
-class P2SHBitcoinAddress(CBitcoinAddress):
+class P2SHBitcoinAddress(CBase58BitcoinAddress):
     @classmethod
     def from_bytes(cls, data, nVersion=None):
         if nVersion is None:
@@ -112,7 +183,11 @@ def to_scriptPubKey(self):
         assert self.nVersion == bitcoin.params.BASE58_PREFIXES['SCRIPT_ADDR']
         return script.CScript([script.OP_HASH160, self, script.OP_EQUAL])
 
-class P2PKHBitcoinAddress(CBitcoinAddress):
+    def to_redeemScript(self):
+        return self.to_scriptPubKey()
+
+
+class P2PKHBitcoinAddress(CBase58BitcoinAddress):
     @classmethod
     def from_bytes(cls, data, nVersion=None):
         if nVersion is None:
@@ -204,6 +279,55 @@ def to_scriptPubKey(self, nested=False):
         assert self.nVersion == bitcoin.params.BASE58_PREFIXES['PUBKEY_ADDR']
         return script.CScript([script.OP_DUP, script.OP_HASH160, self, script.OP_EQUALVERIFY, script.OP_CHECKSIG])
 
+    def to_redeemScript(self):
+        return self.to_scriptPubKey()
+
+
+class P2WSHBitcoinAddress(CBech32BitcoinAddress):
+
+    @classmethod
+    def from_scriptPubKey(cls, scriptPubKey):
+        """Convert a scriptPubKey to a P2WSH address
+
+        Raises CBitcoinAddressError if the scriptPubKey isn't of the correct
+        form.
+        """
+        if scriptPubKey.is_witness_v0_scripthash():
+            return cls.from_bytes(0, scriptPubKey[2:34])
+        else:
+            raise CBitcoinAddressError('not a P2WSH scriptPubKey')
+
+    def to_scriptPubKey(self):
+        """Convert an address to a scriptPubKey"""
+        assert self.witver == 0
+        return script.CScript([0, self])
+
+    def to_redeemScript(self):
+        return NotImplementedError("not enough data in p2wsh address to reconstruct redeem script")
+
+
+class P2WPKHBitcoinAddress(CBech32BitcoinAddress):
+
+    @classmethod
+    def from_scriptPubKey(cls, scriptPubKey):
+        """Convert a scriptPubKey to a P2WSH address
+
+        Raises CBitcoinAddressError if the scriptPubKey isn't of the correct
+        form.
+        """
+        if scriptPubKey.is_witness_v0_keyhash():
+            return cls.from_bytes(0, scriptPubKey[2:22])
+        else:
+            raise CBitcoinAddressError('not a P2WSH scriptPubKey')
+
+    def to_scriptPubKey(self):
+        """Convert an address to a scriptPubKey"""
+        assert self.witver == 0
+        return script.CScript([0, self])
+
+    def to_redeemScript(self):
+        return script.CScript([script.OP_DUP, script.OP_HASH160, self, script.OP_EQUALVERIFY, script.OP_CHECKSIG])
+
 class CKey(object):
     """An encapsulated private key
 
@@ -256,6 +380,8 @@ def __init__(self, s):
 __all__ = (
         'CBitcoinAddressError',
         'CBitcoinAddress',
+        'CBase58BitcoinAddress',
+        'CBech32BitcoinAddress',
         'P2SHBitcoinAddress',
         'P2PKHBitcoinAddress',
         'CKey',