""" Copyright (c) 2014 Philippe Teuwen Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. This code is taken from https://github.com/doegox/python-cryptoplus/ """ def number2string(i): """Convert a number to a string Input: long or integer Output: string (big-endian) """ s=hex(i)[2:].rstrip('L') if len(s) % 2: s = '0' + s return s.decode('hex') def number2string_N(i, N): """Convert a number to a string of fixed size i: long or integer N: length of string Output: string (big-endian) """ s = '%0*x' % (N*2, i) return s.decode('hex') def string2number(i): """ Convert a string to a number Input: string (big-endian) Output: long or integer """ return int(i.encode('hex'),16) def xorstring(a,b): """XOR two strings of same length For more complex cases, see CryptoPlus.Cipher.XOR""" assert len(a) == len(b) return number2string_N(string2number(a)^string2number(b), len(a)) class Counter(str): #found here: http://www.lag.net/pipermail/paramiko/2008-February.txt """Necessary for CTR chaining mode Initializing a counter object (ctr = Counter('xxx'), gives a value to the counter object. Everytime the object is called ( ctr() ) it returns the current value and increments it by 1. Input/output is a raw string. Counter value is big endian""" def __init__(self, initial_ctr): if not isinstance(initial_ctr, str): raise TypeError("nonce must be str") self.c = int(initial_ctr.encode('hex'), 16) def __call__(self): # This might be slow, but it works as a demonstration ctr = ("%032x" % (self.c,)).decode('hex') self.c += 1 return ctr