112 lines
3.4 KiB
Python
112 lines
3.4 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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import logging
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from binascii import crc32
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from six import with_metaclass
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WORDLISTS = {}
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_log = logging.getLogger(__name__)
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class WordlistType(type):
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def __new__(cls, name, bases, attrs):
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if bases:
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if 'language_name' not in attrs:
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raise TypeError("Missing language_name for {0}".format(name))
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if 'unique_prefix_length' not in attrs:
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raise TypeError("Missing 'unique_prefix_length' for {0}".format(name))
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if 'word_list' not in attrs:
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raise TypeError("Missing 'word_list' for {0}".format(name))
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if 'english_language_name' not in attrs:
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_log.warn("No 'english_language_name' for {0} using '{1}'".format(name, language_name))
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attrs['english_language_name'] = attrs['language_name']
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if len(attrs['word_list']) != 1626:
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raise TypeError("Wrong word list length for {0}".format(name))
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new_cls = super(WordlistType, cls).__new__(cls, name, bases, attrs)
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if bases:
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WORDLISTS[new_cls.english_language_name] = new_cls
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return new_cls
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class Wordlist(with_metaclass(WordlistType)):
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n = 1626
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@classmethod
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def encode(cls, hex):
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"""Convert hexadecimal string to mnemonic word representation with checksum.
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"""
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out = []
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for i in range(len(hex) // 8):
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word = endian_swap(hex[8*i:8*i+8])
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x = int(word, 16)
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w1 = x % cls.n
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w2 = (x // cls.n + w1) % cls.n
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w3 = (x // cls.n // cls.n + w2) % cls.n
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out += [cls.word_list[w1], cls.word_list[w2], cls.word_list[w3]]
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checksum = cls.get_checksum(" ".join(out))
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out.append(checksum)
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return " ".join(out)
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@classmethod
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def decode(cls, phrase):
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"""Calculate hexadecimal representation of the phrase.
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"""
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phrase = phrase.split(" ")
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out = ""
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for i in range(len(phrase) // 3):
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word1, word2, word3 = phrase[3*i:3*i+3]
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w1 = cls.word_list.index(word1)
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w2 = cls.word_list.index(word2) % cls.n
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w3 = cls.word_list.index(word3) % cls.n
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x = w1 + cls.n *((w2 - w1) % cls.n) + cls.n * cls.n * ((w3 - w2) % cls.n)
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out += endian_swap("%08x" % x)
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return out
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@classmethod
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def get_checksum(cls, phrase):
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"""Given a mnemonic word string, return a string of the computed checksum.
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:rtype: str
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"""
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phrase_split = phrase.split(" ")
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if len(phrase_split) < 12:
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raise ValueError("Invalid mnemonic phrase")
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if len(phrase_split) > 13:
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# Standard format
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phrase = phrase_split[:24]
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else:
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# MyMonero format
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phrase = phrase_split[:12]
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wstr = "".join(word[:cls.unique_prefix_length] for word in phrase)
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wstr = bytearray(wstr.encode('utf-8'))
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z = ((crc32(wstr) & 0xffffffff) ^ 0xffffffff ) >> 0
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z2 = ((z ^ 0xffffffff) >> 0) % len(phrase)
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return phrase_split[z2]
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def get_wordlist(name):
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try:
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return WORDLISTS[name]
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except KeyError:
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raise ValueError("No such word list")
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def list_wordlists():
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return WORDLISTS.keys()
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def endian_swap(word):
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"""Given any string, swap bits and return the result.
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:rtype: str
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"""
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return "".join([word[i:i+2] for i in [6, 4, 2, 0]])
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