Add address validation

.gitignore

@@ -11,4 +11,5 @@ docs/build/*
 venv
 build/
 dist/
+htmlcov/
 *.egg-info/

cardano/address/__init__.py

@@ -0,0 +1,122 @@
+import base58
+
+from ..consts import Era
+
+from .shelley import SHELLEY_ADDR_RE
+from . import bech32
+
+
+def address(addr, wallet=None):
+    if isinstance(addr, Address):
+        return addr  # already instatinated and should be of proper class
+    elif isinstance(addr, (bytes, bytearray)):
+        addr = addr.decode()
+    elif not isinstance(addr, str):
+        raise TypeError(
+            "address() argument must be str, bytes, bytearray or Address instance"
+        )
+    # validation
+    if SHELLEY_ADDR_RE.match(addr):
+        AddressClass = ShelleyAddress
+    elif addr.startswith("DdzFF"):
+        AddressClass = ByronAddress
+    elif addr.startswith("Ae2"):
+        AddressClass = IcarusAddress
+    else:
+        raise ValueError("String {} is not a valid Cardano address".format(addr))
+    return AddressClass(addr, wallet=wallet)
+
+
+class Address(object):
+    """
+    Cardano base address class. Does no validation, it is up to child classes.
+
+    Compares with ``str`` and ``bytes`` objects.
+
+    :param addr:    the address as ``str`` or ``bytes`` or ``Address``
+    :param wallet:  the ``Wallet`` object if address belongs to
+    """
+
+    _address = ""
+    wallet = None
+
+    def __init__(self, addr, wallet=None):
+        self._address = addr
+        self.wallet = wallet or self.wallet
+        self._validate()
+
+    def _validate(self):
+        pass
+
+    def __repr__(self):
+        return str(self._address)
+
+    def __eq__(self, other):
+        if isinstance(other, Address):
+            return str(self) == str(other)
+        elif isinstance(other, str):
+            return str(self) == other
+        elif isinstance(other, bytes):
+            return str(self).encode() == other
+        return super(Address, self).__eq__(other)
+
+    def __hash__(self):
+        return hash(str(self))
+
+    def __format__(self, spec):
+        return format(str(self), spec)
+
+
+class ByronAddress(Address):
+    era = Era.BYRON
+
+    def _validate(self):
+        if not self._address.startswith("DdzFF"):
+            raise ValueError("{:s} is not a valid Byron address".format(self._address))
+        data = base58.b58decode(self._address)
+
+
+class IcarusAddress(ByronAddress):
+    def _validate(self):
+        if not self._address.startswith("Ae2"):
+            raise ValueError(
+                "{:s} is not a valid Icarus/Byron address".format(self._address)
+            )
+        data = base58.b58decode(self._address)
+
+
+class ShelleyAddress(Address):
+    era = Era.SHELLEY
+
+    def _validate(self):
+        hrp, payload32 = bech32.bech32_decode(self._address)
+        if not payload32:
+            raise ValueError(
+                "{:s} is not a valid Shelley address".format(self._address)
+            )
+        payload = bech32.convertbits(payload32, 5, 8, False)
+        addr_typ, net_tag = (payload[0] & 0xF0) >> 4, payload[0] & 0xF
+        if addr_typ > 7 and addr_typ < 0xE:
+            raise ValueError(
+                "Shelley address {:s} is of wrong type (0x{:x})".format(
+                    self._address, addr_typ
+                )
+            )
+        if net_tag not in (0, 1):
+            raise ValueError(
+                "Shelley address {:s} has unsupported net tag (0x{:x})".format(
+                    self._address, net_tag
+                )
+            )
+        if net_tag == 0 and not hrp.endswith("_test"):
+            raise ValueError(
+                'Shelley address {:s} has TESTNET tag but the prefix doesn\'t end with "_test"'.format(
+                    self._address
+                )
+            )
+        elif net_tag == 1 and hrp.endswith("_test"):
+            raise ValueError(
+                'Shelley address {:s} has MAINNET tag but the prefix ends with "_test"'.format(
+                    self._address
+                )
+            )

cardano/address/bech32.py

@@ -0,0 +1,93 @@
+# Copyright (c) 2017, 2020 Pieter Wuille
+# Copyright (c) 2021 Michal Salaban
+#
+# Code taken from
+# https://github.com/sipa/bech32/blob/45bbf67d3dcc00dc960041563fc2dddd32a5f903/ref/python/segwit_addr.py
+# and pruned to match the needs of the cardano module.
+#
+#
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+"""Reference implementation for Bech32/Bech32m and segwit addresses."""
+
+
+from enum import Enum
+
+CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+
+
+def bech32_polymod(values):
+    """Internal function that computes the Bech32 checksum."""
+    generator = [0x3B6A57B2, 0x26508E6D, 0x1EA119FA, 0x3D4233DD, 0x2A1462B3]
+    chk = 1
+    for value in values:
+        top = chk >> 25
+        chk = (chk & 0x1FFFFFF) << 5 ^ value
+        for i in range(5):
+            chk ^= generator[i] if ((top >> i) & 1) else 0
+    return chk
+
+
+def bech32_hrp_expand(hrp):
+    """Expand the HRP into values for checksum computation."""
+    return [ord(x) >> 5 for x in hrp] + [0] + [ord(x) & 31 for x in hrp]
+
+
+def bech32_decode(bech):
+    """Validate a Bech32/Bech32m string, and determine HRP and data."""
+    if (any(ord(x) < 33 or ord(x) > 126 for x in bech)) or (
+        bech.lower() != bech and bech.upper() != bech
+    ):
+        return (None, None, None)
+    bech = bech.lower()
+    pos = bech.rfind("1")
+    if pos < 1 or pos + 7 > len(bech):
+        # Removed the 90 char limitation -- MS
+        return (None, None, None)
+    if not all(x in CHARSET for x in bech[pos + 1 :]):
+        return (None, None, None)
+    hrp = bech[:pos]
+    data = [CHARSET.find(x) for x in bech[pos + 1 :]]
+    if bech32_polymod(bech32_hrp_expand(hrp) + data) is None:
+        return (None, None, None)
+    return (hrp, data[:-6])
+
+
+def convertbits(data, frombits, tobits, pad=True):
+    """General power-of-2 base conversion."""
+    acc = 0
+    bits = 0
+    ret = []
+    maxv = (1 << tobits) - 1
+    max_acc = (1 << (frombits + tobits - 1)) - 1
+    for value in data:
+        if value < 0 or (value >> frombits):
+            return None
+        acc = ((acc << frombits) | value) & max_acc
+        bits += frombits
+        while bits >= tobits:
+            bits -= tobits
+            ret.append((acc >> bits) & maxv)
+    if pad:  # pragma: no cover
+        if bits:
+            ret.append((acc << (tobits - bits)) & maxv)
+    elif bits >= frombits or ((acc << (tobits - bits)) & maxv):
+        return None
+    return ret

cardano/address/shelley.py

@@ -0,0 +1,53 @@
+import re
+
+PREFIXES = [
+    "addr",
+    "addr_test",
+    "script",
+    "stake",
+    "stake_test"
+    #      -- * Hashes
+    ,
+    "addr_vkh",
+    "stake_vkh",
+    "addr_shared_vkh",
+    "stake_shared_vkh"
+    #      -- * Keys for 1852H
+    ,
+    "addr_vk",
+    "addr_sk",
+    "addr_xvk",
+    "addr_xsk",
+    "acct_vk",
+    "acct_sk",
+    "acct_xvk",
+    "acct_xsk",
+    "root_vk",
+    "root_sk",
+    "root_xvk",
+    "root_xsk",
+    "stake_vk",
+    "stake_sk",
+    "stake_xvk",
+    "stake_xsk"
+    #      -- * Keys for 1854H
+    ,
+    "addr_shared_vk",
+    "addr_shared_sk",
+    "addr_shared_xvk",
+    "addr_shared_xsk",
+    "acct_shared_vk",
+    "acct_shared_sk",
+    "acct_shared_xvk",
+    "acct_shared_xsk",
+    "root_shared_vk",
+    "root_shared_sk",
+    "root_shared_xvk",
+    "root_shared_xsk",
+    "stake_shared_vk",
+    "stake_shared_sk",
+    "stake_shared_xvk",
+    "stake_shared_xsk",
+]
+
+SHELLEY_ADDR_RE = re.compile("^(" + "|".join(PREFIXES) + ")")

requirements.txt

@@ -1 +1,2 @@
+base58
 requests