RSA version 1.1 released
A pure Python implementation of the RSA cryptographic protocol. It contains functions for encryption, decryption, signing, verification, and the generation of keys and prime numbers.
The recursive nature of RSA version 1.0 prevented the use of large keys. Thanks to Miguel Angel Vilela of the Google Enterprise Support Team version 1.1 handles large keys just fine.
The RSA module page contains the download links and examples.
More info on the use of RSA in Google Apps on App Engine Fan’s AppEngine and Encryption blog entry.