Simon Willison’s Weblog

Easy Python Cryptography

14th April 2003

Via Garth Kidd’s Python cryptography roundup, ezPyCrypto is a cryptography API so simple even I can use it. Unfortunately the example code is only available in the download archive (not on the web site) but here’s an overview of how it works:

import ezPyCrypto
# Generate a 512 bit key
key = ezPyCrypto.key(512)

text = 'This will be encrypted'

# Encrypt the string
encrypted = key.encString(text)
print encrypted

# Unencrypt the string
decrypted = key.decString(encrypted)
print decrypted

# Export the public key
public = key.exportKey()
# This can now be saved or distributed

# Export the private key
private = key.exportKeyPrivate()
# This can now be saved somewhere safe

# Encrypting using an already generated public key:
key = ezPyCrypto.key()
key.importKey(public)
encrypted = key.encString(text)

# Decrypting using an already generated private key:
key = ezPyCrypto.key()
key.importKey(private)
decrypted = key.decString(text)

That’s pretty much it. The class also has support for passphrases which can be used to add an extra layer of protection to a private key, as well as methods to handle crypotgraphic signing and verification.

ezPyCrypto is an easy to use wrapper for the excellent PyCrypto module, and includes PyCrypto (and a handy Windows installer) in the distribution.