Merge pull request #3 from starcoinorg/bech32

Implement ReceiptIdentifier

Author: sanlee42

starcoin/sdk/bech32.py

@@ -0,0 +1,135 @@
+# Copyright (c) 2017, 2020 Pieter Wuille
+#
+# 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
+
+
+class Encoding(Enum):
+    """Enumeration type to list the various supported encodings."""
+    BECH32 = 1
+    BECH32M = 2
+
+
+CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+BECH32M_CONST = 0x2bc830a3
+
+
+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_verify_checksum(hrp, data):
+    """Verify a checksum given HRP and converted data characters."""
+    const = bech32_polymod(bech32_hrp_expand(hrp) + data)
+    if const == 1:
+        return Encoding.BECH32
+    if const == BECH32M_CONST:
+        return Encoding.BECH32M
+    return None
+
+
+def bech32_create_checksum(hrp, data, spec):
+    """Compute the checksum values given HRP and data."""
+    values = bech32_hrp_expand(hrp) + data
+    const = BECH32M_CONST if spec == Encoding.BECH32M else 1
+    polymod = bech32_polymod(values + [0, 0, 0, 0, 0, 0]) ^ const
+    return [(polymod >> 5 * (5 - i)) & 31 for i in range(6)]
+
+
+def bech32_encode(hrp, data, spec):
+    """Compute a Bech32 string given HRP and data values."""
+    combined = data + bech32_create_checksum(hrp, data, spec)
+    return hrp + '1' + ''.join([CHARSET[d] for d in combined])
+
+
+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) or len(bech) > 90:
+        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:]]
+    spec = bech32_verify_checksum(hrp, data)
+    if spec is None:
+        return (None, None, None)
+    return (hrp, data[:-6], spec)
+
+
+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:
+        if bits:
+            ret.append((acc << (tobits - bits)) & maxv)
+    elif bits >= frombits or ((acc << (tobits - bits)) & maxv):
+        return None
+    return ret
+
+
+def decode(hrp, addr):
+    """Decode a segwit address."""
+    hrpgot, data, spec = bech32_decode(addr)
+    if hrpgot != hrp:
+        return None
+    decoded = convertbits(data[1:], 5, 8, False)
+    return (data[0], decoded)
+
+
+def encode(hrp, witver, witprog):
+    """Encode a segwit address."""
+    ret = bech32_encode(
+        hrp, [witver] + convertbits(witprog, 8, 5), Encoding.BECH32)
+    if decode(hrp, ret) == (None, None):
+        return None
+    return ret

starcoin/sdk/receipt_identifier.py

@@ -0,0 +1,38 @@
+from starcoin.sdk.auth_key import AuthKey
+from starcoin.starcoin_types import AccountAddress
+from typing import Union
+from starcoin.sdk import bech32
+from starcoin.sdk import utils
+
+
+class ReceiptIdentifier:
+    """
+    ref: [sip-21](https://github.com/starcoinorg/SIPs/blob/master/sip-21/index.md)
+    """
+    account_address: AccountAddress
+    auth_key: Union[AuthKey, None]
+
+    def __init__(self, account_address: AccountAddress,
+                 auth_key: Union[AuthKey, None]):
+        self.account_address = account_address
+        self.auth_key = auth_key
+
+    def encode(self) -> "str":
+        data = bytearray(self.account_address.bcs_serialize())
+        if isinstance(self.auth_key, AuthKey):
+            data.extend(bytearray(self.auth_key.data))
+        return bech32.encode("stc", 1, data)
+
+    @staticmethod
+    def decode(s: str) -> "ReceiptIdentifier":
+        (version, data) = bech32.decode("stc", s)
+        if version != 1:
+            return None
+        address = AccountAddress.from_hex(
+            bytearray(data[0:utils.ACCOUNT_ADDRESS_LEN]).hex())
+        if len(data) == utils.ACCOUNT_ADDRESS_LEN:
+            auth_key = None
+        else:
+            auth_key = AuthKey(bytes(data[utils.ACCOUNT_ADDRESS_LEN:]))
+
+        return ReceiptIdentifier(address, auth_key)

starcoin/starcoin_types/__init__.py

@@ -34,7 +34,7 @@ def bcs_deserialize(input: bytes) -> 'AccessPath':
         if buffer:
             raise st.DeserializationError("Some input bytes were not read")
         return v
-    
+
 
 @dataclass(frozen=True)
 class AccountAddress:
@@ -56,6 +56,7 @@ def from_hex(addr: str) -> 'AccountAddress':
         """Create an account address from bytes."""
         return AccountAddress(tuple(st.uint8(x) for x in bytes.fromhex(addr)))
 
+
 @dataclass(frozen=True)
 class AccountResource:
     authentication_key: bytes

tests/test_receipt_identifier.py

@@ -0,0 +1,19 @@
+from starcoin.sdk.receipt_identifier import ReceiptIdentifier
+from starcoin.starcoin_types import AccountAddress
+from starcoin.sdk.auth_key import AuthKey
+from starcoin.sdk import utils
+
+
+def test_receipt_identifier():
+    auth_key_hex = "93dcc435cfca2dcf3bf44e9948f1f6a98e66a1f1b114a4b8a37ea16e12beeb6d"
+    address_hex = "1603d10ce8649663e4e5a757a8681833"
+
+    # encode
+    receipt = ReceiptIdentifier(
+        AccountAddress.from_hex(address_hex), AuthKey(bytes.fromhex(auth_key_hex))).encode()
+    # deocode
+    decode_receipt = ReceiptIdentifier.decode(receipt)
+
+    assert utils.account_address_hex(
+        decode_receipt.account_address) == address_hex
+    assert decode_receipt.auth_key.hex() == auth_key_hex