diff --git a/Demo/pdist/security.py b/Demo/pdist/security.py
new file mode 100755
index 0000000..29bc945
--- /dev/null
+++ b/Demo/pdist/security.py
@@ -0,0 +1,26 @@
+class Security:
+
+	def __init__(self):
+		import os
+		env = os.environ
+		if env.has_key('PYTHON_KEYFILE'):
+			keyfile = env['PYTHON_KEYFILE']
+		elif env.has_key('HOME'):
+			keyfile = env['HOME'] + '.python_keyfile'
+		else:
+			keyfile = '.python_keyfile'
+		try:
+			self._key = eval(open(keyfile).readline())
+		except IOError:
+			raise IOError, "python keyfile %s not found" % keyfile
+
+	def _generate_challenge(self):
+		import whrandom
+		return whrandom.randint(100, 100000)
+
+	def _compare_challenge_response(self, challenge, response):
+		return self._encode_challenge(challenge) == response
+
+	def _encode_challenge(self, challenge):
+		p, m = self._key
+		return pow(challenge, p, m)