1badc5f38c
-move base58.py and bip32.py into scribe.schema -fix https://github.com/lbryio/scribe/issues/3
111 lines
3 KiB
Python
111 lines
3 KiB
Python
import hashlib
|
|
|
|
|
|
def sha256(x):
|
|
""" Simple wrapper of hashlib sha256. """
|
|
return hashlib.sha256(x).digest()
|
|
|
|
|
|
def double_sha256(x):
|
|
""" SHA-256 of SHA-256, as used extensively in bitcoin. """
|
|
return sha256(sha256(x))
|
|
|
|
|
|
class Base58Error(Exception):
|
|
""" Exception used for Base58 errors. """
|
|
|
|
|
|
_CHARS = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
|
|
|
|
|
|
def _iter_encode(be_bytes: bytes):
|
|
value = int.from_bytes(be_bytes, 'big')
|
|
while value:
|
|
value, mod = divmod(value, 58)
|
|
yield _CHARS[mod]
|
|
for byte in be_bytes:
|
|
if byte != 0:
|
|
break
|
|
yield '1'
|
|
|
|
|
|
def b58_encode(be_bytes: bytes):
|
|
return ''.join(_iter_encode(be_bytes))[::-1]
|
|
|
|
|
|
class Base58:
|
|
""" Class providing base 58 functionality. """
|
|
|
|
chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
|
|
assert len(chars) == 58
|
|
char_map = {c: n for n, c in enumerate(chars)}
|
|
|
|
@classmethod
|
|
def char_value(cls, c):
|
|
val = cls.char_map.get(c)
|
|
if val is None:
|
|
raise Base58Error(f'invalid base 58 character "{c}"')
|
|
return val
|
|
|
|
@classmethod
|
|
def decode(cls, txt):
|
|
""" Decodes txt into a big-endian bytearray. """
|
|
if isinstance(txt, memoryview):
|
|
txt = str(txt)
|
|
|
|
if isinstance(txt, bytes):
|
|
txt = txt.decode()
|
|
|
|
if not isinstance(txt, str):
|
|
raise TypeError(f'a string is required, got {type(txt).__name__}')
|
|
|
|
if not txt:
|
|
raise Base58Error('string cannot be empty')
|
|
|
|
value = 0
|
|
for c in txt:
|
|
value = value * 58 + cls.char_value(c)
|
|
|
|
result = value.to_bytes((value.bit_length() + 7) // 8, 'big')
|
|
|
|
# Prepend leading zero bytes if necessary
|
|
count = 0
|
|
for c in txt:
|
|
if c != '1':
|
|
break
|
|
count += 1
|
|
if count:
|
|
result = bytes((0,)) * count + result
|
|
|
|
return result
|
|
|
|
@classmethod
|
|
def _iter_encode(cls, be_bytes: bytes):
|
|
value = int.from_bytes(be_bytes, 'big')
|
|
while value:
|
|
value, mod = divmod(value, 58)
|
|
yield cls.chars[mod]
|
|
for byte in be_bytes:
|
|
if byte != 0:
|
|
break
|
|
yield '1'
|
|
|
|
@classmethod
|
|
def encode(cls, be_bytes):
|
|
return ''.join(cls._iter_encode(be_bytes))[::-1]
|
|
|
|
@classmethod
|
|
def decode_check(cls, txt, hash_fn=double_sha256):
|
|
""" Decodes a Base58Check-encoded string to a payload. The version prefixes it. """
|
|
be_bytes = cls.decode(txt)
|
|
result, check = be_bytes[:-4], be_bytes[-4:]
|
|
if check != hash_fn(result)[:4]:
|
|
raise Base58Error(f'invalid base 58 checksum for {txt}')
|
|
return result
|
|
|
|
@classmethod
|
|
def encode_check(cls, payload, hash_fn=double_sha256):
|
|
""" Encodes a payload bytearray (which includes the version byte(s))
|
|
into a Base58Check string."""
|
|
be_bytes = payload + hash_fn(payload)[:4]
|
|
return b58_encode(be_bytes)
|