A cheap example of HMAC in python.

sign.py

import base64
import urllib
import hashlib
import hmac

def sign_url(url, key='test'):
	h = hmac.new(bytes(key), url, digestmod=hashlib.sha1)
	hmacs = urllib.quote_plus(base64.b64encode(h.digest()))
	return url + '&hmac=' + hmacs
	

# Usage:
# python sign.py url [key]
# (i.e. the url parameter must always be present)
import sys
print sign_url(*sys.argv[1:])