Is there any known way to sign plain text string with RSA secret key in Google App Engine Python SDK?
The tlslite library included in the python gdata library is a good option.
http://code.google.com/p/gdata-python-client/
Example:
from tlslite.utils import keyfactory private_key = keyfactory.parsePrivateKey(rsa_key) signed = private_key.hashAndSign(data)
I have not used it, but it seems to be an RSA implementation with pure Python, so it can work on the App Engine:
http://stuvel.eu/rsa
Their mercurial repo is also quite active.