| # The MIT License (MIT) |
| # |
| # Copyright (c) 2014 Richard Moore |
| # |
| # 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. |
| |
| # Why to_bufferable? |
| # Python 3 is very different from Python 2.x when it comes to strings of text |
| # and strings of bytes; in Python 3, strings of bytes do not exist, instead to |
| # represent arbitrary binary data, we must use the "bytes" object. This method |
| # ensures the object behaves as we need it to. |
| |
| def to_bufferable(binary): |
| return binary |
| |
| def _get_byte(c): |
| return ord(c) |
| |
| try: |
| xrange |
| except: |
| |
| def to_bufferable(binary): |
| if isinstance(binary, bytes): |
| return binary |
| return bytes(ord(b) for b in binary) |
| |
| def _get_byte(c): |
| return c |
| |
| def append_PKCS7_padding(data): |
| pad = 16 - (len(data) % 16) |
| return data + to_bufferable(chr(pad) * pad) |
| |
| def strip_PKCS7_padding(data): |
| if len(data) % 16 != 0: |
| raise ValueError("invalid length") |
| |
| pad = _get_byte(data[-1]) |
| |
| if pad > 16: |
| raise ValueError("invalid padding byte") |
| |
| return data[:-pad] |