1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
'''Base58 encoding
Implementations of Base58 and Base58Check encodings that are compatible
with the bitcoin network.
'''
# This module is based upon base58 snippets found scattered over many bitcoin
# tools written in python. From what I gather the original source is from a
# forum post by Gavin Andresen, so direct your praise to him.
# This module adds shiny packaging and support for python3.
from hashlib import sha256
from typing import Union
__version__ = '2.0.1'
# 58 character alphabet used
BITCOIN_ALPHABET = \
b'123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
RIPPLE_ALPHABET = b'rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz'
# Retro compatibility
alphabet = BITCOIN_ALPHABET
def scrub_input(v: Union[str, bytes]) -> bytes:
if isinstance(v, str):
v = v.encode('ascii')
return v
def b58encode_int(
i: int, default_one: bool = True, alphabet: bytes = BITCOIN_ALPHABET
) -> bytes:
"""
Encode an integer using Base58
"""
if not i and default_one:
return alphabet[0:1]
string = b""
while i:
i, idx = divmod(i, 58)
string = alphabet[idx:idx+1] + string
return string
def b58encode(
v: Union[str, bytes], alphabet: bytes = BITCOIN_ALPHABET
) -> bytes:
"""
Encode a string using Base58
"""
v = scrub_input(v)
nPad = len(v)
v = v.lstrip(b'\0')
nPad -= len(v)
p, acc = 1, 0
for c in reversed(v):
acc += p * c
p = p << 8
result = b58encode_int(acc, default_one=False, alphabet=alphabet)
return alphabet[0:1] * nPad + result
def b58decode_int(
v: Union[str, bytes], alphabet: bytes = BITCOIN_ALPHABET
) -> int:
"""
Decode a Base58 encoded string as an integer
"""
v = v.rstrip()
v = scrub_input(v)
decimal = 0
for char in v:
decimal = decimal * 58 + alphabet.index(char)
return decimal
def b58decode(
v: Union[str, bytes], alphabet: bytes = BITCOIN_ALPHABET
) -> bytes:
"""
Decode a Base58 encoded string
"""
v = v.rstrip()
v = scrub_input(v)
origlen = len(v)
v = v.lstrip(alphabet[0:1])
newlen = len(v)
acc = b58decode_int(v, alphabet=alphabet)
result = []
while acc > 0:
acc, mod = divmod(acc, 256)
result.append(mod)
return b'\0' * (origlen - newlen) + bytes(reversed(result))
def b58encode_check(
v: Union[str, bytes], alphabet: bytes = BITCOIN_ALPHABET
) -> bytes:
"""
Encode a string using Base58 with a 4 character checksum
"""
v = scrub_input(v)
digest = sha256(sha256(v).digest()).digest()
return b58encode(v + digest[:4], alphabet=alphabet)
def b58decode_check(
v: Union[str, bytes], alphabet: bytes = BITCOIN_ALPHABET
) -> bytes:
'''Decode and verify the checksum of a Base58 encoded string'''
result = b58decode(v, alphabet=alphabet)
result, check = result[:-4], result[-4:]
digest = sha256(sha256(result).digest()).digest()
if check != digest[:4]:
raise ValueError("Invalid checksum")
return result
|