118 lines
3.7 KiB
Python
118 lines
3.7 KiB
Python
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from Cryptodome import Random
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import binascii
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import math
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def bytes_to_hex(buffer: bytes) -> str:
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"""
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Convert bytes to hex
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Args:
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buffer: Bytes to convert
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Returns:
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hex
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"""
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return binascii.hexlify(buffer).decode()
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def hex_to_bytes(s: str) -> bytes:
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return binascii.unhexlify(s)
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def int_to_bytes(i: int):
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"""
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Convert an integer to a byte(s)
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Args:
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i: Integer to convert
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Returns:
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bytes
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"""
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width = i.bit_length()
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width += 8 - ((width % 8) or 8)
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fmt = '%%0%dx' % (width // 4)
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return b"\x00" if i == 0 else binascii.unhexlify(fmt % i)
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def random_hex_string(length: int):
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buffer = Random.get_random_bytes(int(length / 2))
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return bytes_to_hex(buffer)
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class Base62:
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standard_base = 256
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target_base = 62
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alphabet: bytes
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lookup: bytearray
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def __init__(self, alphabet: bytes):
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self.alphabet = alphabet
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self.create_lookup_table()
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@staticmethod
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def create_instance_with_inverted_character_set():
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return Base62(Base62.CharacterSets.inverted)
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def encode(self, message: bytes, length: int = -1):
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indices = self.convert(message, self.standard_base, self.target_base,
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length)
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return self.translate(indices, self.alphabet)
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def decode(self, encoded: bytes, length: int = -1):
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prepared = self.translate(encoded, self.lookup)
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return self.convert(prepared, self.target_base, self.standard_base,
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length)
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def translate(self, indices: bytes, dictionary: bytes):
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translation = bytearray(len(indices))
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for i in range(len(indices)):
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translation[i] = dictionary[int.from_bytes(bytes([indices[i]]), "big")]
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return translation
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def convert(self, message: bytes, source_base: int, target_base: int,
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length: int):
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estimated_length = self.estimate_output_length(
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len(message), source_base, target_base) if length == -1 else length
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out = b""
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source = message
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while len(source) > 0:
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quotient = b""
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remainder = 0
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for b in source:
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accumulator = int(b & 0xff) + remainder * source_base
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digit = int(
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(accumulator - (accumulator % target_base)) / target_base)
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remainder = int(accumulator % target_base)
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if len(quotient) > 0 or digit > 0:
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quotient += bytes([digit])
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out += bytes([remainder])
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source = quotient
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if len(out) < estimated_length:
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size = len(out)
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for _ in range(estimated_length - size):
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out += bytes([0])
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return self.reverse(out)
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if len(out) > estimated_length:
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return self.reverse(out[:estimated_length])
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return self.reverse(out)
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def estimate_output_length(self, input_length: int, source_base: int,
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target_base: int):
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return int(
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math.ceil((math.log(source_base) / math.log(target_base)) *
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input_length))
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def reverse(self, arr: bytes):
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length = len(arr)
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reversed_arr = bytearray(length)
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for i in range(length):
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reversed_arr[length - i - 1] = arr[i]
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return bytes(reversed_arr)
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def create_lookup_table(self):
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self.lookup = bytearray(256)
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for i in range(len(self.alphabet)):
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self.lookup[self.alphabet[i]] = i & 0xff
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class CharacterSets:
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gmp = b'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
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inverted = b'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
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