| Python Cryptography Toolkit (pycrypto) |
| ====================================== |
| |
| This is a collection of both secure hash functions (such as SHA256 and |
| RIPEMD160), and various encryption algorithms (AES, DES, RSA, ElGamal, |
| etc.). The package is structured to make adding new modules easy. |
| This section is essentially complete, and the software interface will |
| almost certainly not change in an incompatible way in the future; all |
| that remains to be done is to fix any bugs that show up. If you |
| encounter a bug, please report it in the Launchpad bug tracker at |
| |
| https://launchpad.net/products/pycrypto/+bugs |
| |
| An example usage of the SHA256 module is: |
| >>> from Crypto.Hash import SHA256 |
| >>> hash = SHA256.new() |
| >>> hash.update('message') |
| >>> hash.digest() |
| '\xabS\n\x13\xe4Y\x14\x98+y\xf9\xb7\xe3\xfb\xa9\x94\xcf\xd1\xf3\xfb"\xf7\x1c\xea\x1a\xfb\xf0+F\x0cm\x1d' |
| |
| An example usage of an encryption algorithm (AES, in this case) is: |
| |
| >>> from Crypto.Cipher import AES |
| >>> obj = AES.new('This is a key456', AES.MODE_ECB) |
| >>> message = "The answer is no" |
| >>> ciphertext = obj.encrypt(message) |
| >>> ciphertext |
| 'o\x1aq_{P+\xd0\x07\xce\x89\xd1=M\x989' |
| >>> obj2 = AES.new('This is a key456', AES.MODE_ECB) |
| >>> obj2.decrypt(ciphertext) |
| 'The answer is no' |
| |
| One possible application of the modules is writing secure |
| administration tools. Another application is in writing daemons and |
| servers. Clients and servers can encrypt the data being exchanged and |
| mutually authenticate themselves; daemons can encrypt private data for |
| added security. Python also provides a pleasant framework for |
| prototyping and experimentation with cryptographic algorithms; thanks |
| to its arbitrary-length integers, public key algorithms are easily |
| implemented. |
| |
| As of PyCrypto 2.1.0, PyCrypto provides an easy-to-use random number |
| generator: |
| |
| >>> from Crypto import Random |
| >>> rndfile = Random.new() |
| >>> rndfile.read(16) |
| '\xf7.\x838{\x85\xa0\xd3>#}\xc6\xc2jJU' |
| |
| A stronger version of Python's standard "random" module is also |
| provided: |
| |
| >>> from Crypto.Random import random |
| >>> random.choice(['dogs', 'cats', 'bears']) |
| 'bears' |
| |
| Caveat: For the random number generator to work correctly, you must |
| call Random.atfork() in both the parent and child processes after |
| using os.fork() |
| |
| |
| Installation |
| ============ |
| |
| PyCrypto is written and tested using Python version 2.1 through 2.6, |
| though support for Python 2.1 will be dropped soon. Python 1.5.2 is |
| not supported. |
| |
| The modules are packaged using the Distutils, so you can simply run |
| "python setup.py build" to build the package, and "python setup.py |
| install" to install it. |
| |
| If the setup.py script crashes with a DistutilsPlatformError |
| complaining that the file /usr/lib/python2.2/config/Makefile doesn't |
| exist, this means that the files needed for compiling new Python |
| modules aren't installed on your system. Red Hat users often run into |
| this because they don't have the python2-devel RPM installed. The fix |
| is to simply install the requisite RPM. On Debian/Ubuntu, you need the |
| python-dev package. |
| |
| To verify that everything is in order, run "python setup.py test". It |
| will test all the cryptographic modules, skipping ones that aren't |
| available. If the test script reports an error on your machine, |
| please report the bug using the bug tracker (URL given above). If |
| possible, track down the bug and include a patch that fixes it, |
| provided that you are able to meet the eligibility requirements at |
| http://www.pycrypto.org/submission-requirements/. |
| |
| It is possible to test a single sub-package or a single module only, for instance |
| when you investigate why certain tests fail and don't want to run the whole |
| suite each time. Use "python setup.py test --module=name", where 'name' |
| is either a sub-package (Cipher, PublicKey, etc) or a module (Cipher.DES, |
| PublicKey.RSA, etc). |
| To further cut test coverage, pass also the option "--skip-slow-tests". |
| |
| To install the package under the site-packages directory of |
| your Python installation, run "python setup.py install". |
| |
| If you have any comments, corrections, or improvements for this |
| package, please report them to our mailing list, accessible via the |
| PyCrypto website: |
| |
| http://www.pycrypto.org/ |
| |
