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- """
- Copyright (c) 2014 Philippe Teuwen <phil@teuwen.org>
- 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
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