PyCrypto BlockCipher Adapter
This project shows how to extend PyCrypto with your own ciphers.
In PyCrypto the various ciphering modes are added to a block cipher in two steps.
First the basic ciphering modes:
CTR, these are added
to a cipher in a C file: block_template.c. This only works for the ciphers
bundled with PyCrypto.
The more complicated ciphering modes (
are added to a cipher by building upon the simple modes, in Crypto/Cipher/blockalgo.py
So if you want to use blockalgo to add
CCM to your own cipher, you will have to make sure it supports the simple ciphering modes first.
You can do this by deriving from the
_BlockCipher class offered here.
It expects the user to implement only the
In order to add the more complex modes you can pass the above cipher as the factory class
BlockAlgo derived object.
Three examples are provided:
- AESCipher : should behave exactly the same as
Crypto.Cipher.AES- for testing.
- TandemCipher : A Cipher as used in GSMK cryptophone, XORring AES and Twofish.
- TwofishCipher: wraps the twofish module, adding PyCrypto ciphering modes.
- Modes.py: For the purpose of testing the
CipherAdapter, several wrappers which add a ciphering mode to a cipher, using only it's ECB mode.
Note that in
new factory method is in the top level class,
while in the
TwofishCipher module the
new method is a module level function.
These are implemented differently showing two different ways of implementing a cipher.
- For CFB mode currently only
Author: Willem Hengeveld email@example.com