152 lines
4.5 KiB
Python
152 lines
4.5 KiB
Python
# MoneroPy - A python toolbox for Monero
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# Copyright (C) 2016 The MoneroPy Developers.
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#
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# MoneroPy is released under the BSD 3-Clause license. Use and redistribution of
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# this software is subject to the license terms in the LICENSE file found in the
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# top-level directory of this distribution.
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#
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# Modified by emesik and rooterkyberian:
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# + optimized
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# + proper exceptions instead of returning errors as results
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__alphabet = [ord(s) for s in '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz']
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__b58base = 58
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__UINT64MAX = 2**64
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__encodedBlockSizes = [0, 2, 3, 5, 6, 7, 9, 10, 11]
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__fullBlockSize = 8
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__fullEncodedBlockSize = 11
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def _hexToBin(hex_):
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if len(hex_) % 2 != 0:
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raise ValueError("Hex string has invalid length: %d" % len(hex_))
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return [int(hex_[i:i + 2], 16) for i in range(0, len(hex_), 2)]
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def _binToHex(bin_):
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return "".join('%02x' % int(b) for b in bin_)
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def _uint8be_to_64(data):
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if not (1 <= len(data) <= 8):
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raise ValueError("Invalid input length: %d" % len(data))
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res = 0
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for b in data:
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res = res << 8 | b
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return res
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def _uint64_to_8be(num, size):
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if size < 1 or size > 8:
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raise ValueError("Invalid input length: %d" % size)
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res = [0] * size
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twopow8 = 2**8
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for i in range(size-1,-1,-1):
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res[i] = num % twopow8
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num = num // twopow8
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return res
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def encode_block(data, buf, index):
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l_data = len(data)
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if l_data < 1 or l_data > __fullEncodedBlockSize:
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raise ValueError("Invalid block length: %d" % l_data)
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num = _uint8be_to_64(data)
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i = __encodedBlockSizes[l_data] - 1
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while num > 0:
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remainder = num % __b58base
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num = num // __b58base
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buf[index+i] = __alphabet[remainder]
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i -= 1
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return buf
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def encode(hex):
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'''Encode hexadecimal string as base58 (ex: encoding a Monero address).'''
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data = _hexToBin(hex)
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l_data = len(data)
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if l_data == 0:
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return ""
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full_block_count = l_data // __fullBlockSize
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last_block_size = l_data % __fullBlockSize
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res_size = full_block_count * __fullEncodedBlockSize + __encodedBlockSizes[last_block_size]
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res = bytearray([__alphabet[0]] * res_size)
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for i in range(full_block_count):
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res = encode_block(data[(i*__fullBlockSize):(i*__fullBlockSize+__fullBlockSize)], res, i * __fullEncodedBlockSize)
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if last_block_size > 0:
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res = encode_block(data[(full_block_count*__fullBlockSize):(full_block_count*__fullBlockSize+last_block_size)], res, full_block_count * __fullEncodedBlockSize)
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return bytes(res).decode('ascii')
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def decode_block(data, buf, index):
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l_data = len(data)
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if l_data < 1 or l_data > __fullEncodedBlockSize:
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raise ValueError("Invalid block length: %d" % l_data)
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res_size = __encodedBlockSizes.index(l_data)
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if res_size <= 0:
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raise ValueError("Invalid block size: %d" % res_size)
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res_num = 0
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order = 1
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for i in range(l_data-1, -1, -1):
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digit = __alphabet.index(data[i])
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if digit < 0:
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raise ValueError("Invalid symbol: %s" % data[i])
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product = order * digit + res_num
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if product > __UINT64MAX:
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raise ValueError("Overflow: %d * %d + %d = %d" % (order, digit, res_num, product))
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res_num = product
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order = order * __b58base
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if res_size < __fullBlockSize and 2**(8 * res_size) <= res_num:
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raise ValueError("Overflow: %d doesn't fit in %d bit(s)" % (res_num, res_size))
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tmp_buf = _uint64_to_8be(res_num, res_size)
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buf[index:index + len(tmp_buf)] = tmp_buf
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return buf
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def decode(enc):
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'''Decode a base58 string (ex: a Monero address) into hexidecimal form.'''
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enc = bytearray(enc, encoding='ascii')
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l_enc = len(enc)
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if l_enc == 0:
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return ""
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full_block_count = l_enc // __fullEncodedBlockSize
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last_block_size = l_enc % __fullEncodedBlockSize
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try:
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last_block_decoded_size = __encodedBlockSizes.index(last_block_size)
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except ValueError:
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raise ValueError("Invalid encoded length: %d" % l_enc)
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data_size = full_block_count * __fullBlockSize + last_block_decoded_size
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data = bytearray(data_size)
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for i in range(full_block_count):
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data = decode_block(enc[(i*__fullEncodedBlockSize):(i*__fullEncodedBlockSize+__fullEncodedBlockSize)], data, i * __fullBlockSize)
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if last_block_size > 0:
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data = decode_block(enc[(full_block_count*__fullEncodedBlockSize):(full_block_count*__fullEncodedBlockSize+last_block_size)], data, full_block_count * __fullBlockSize)
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return _binToHex(data)
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