python-trezor/trezorlib/tools.py
2013-12-30 23:34:56 +01:00

56 lines
1.3 KiB
Python

__b58chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
__b58base = len(__b58chars)
def b58encode(v):
""" encode v, which is a string of bytes, to base58."""
long_value = 0L
for (i, c) in enumerate(v[::-1]):
long_value += (256 ** i) * ord(c)
result = ''
while long_value >= __b58base:
div, mod = divmod(long_value, __b58base)
result = __b58chars[mod] + result
long_value = div
result = __b58chars[long_value] + result
# Bitcoin does a little leading-zero-compression:
# leading 0-bytes in the input become leading-1s
nPad = 0
for c in v:
if c == '\0':
nPad += 1
else:
break
return (__b58chars[0] * nPad) + result
def b58decode(v, length):
""" decode v into a string of len bytes."""
long_value = 0L
for (i, c) in enumerate(v[::-1]):
long_value += __b58chars.find(c) * (__b58base ** i)
result = ''
while long_value >= 256:
div, mod = divmod(long_value, 256)
result = chr(mod) + result
long_value = div
result = chr(long_value) + result
nPad = 0
for c in v:
if c == __b58chars[0]:
nPad += 1
else:
break
result = chr(0) * nPad + result
if length is not None and len(result) != length:
return None
return result