Merge pull request #1219 from mithodin/9733-mithodin-digestmod

Author: mithodin

Reviewer: glyph

Fixes: ticket:9733

CramMD5ClientAuthenticator now specifies the digestmod argument to hmac.HMAC constructor explicitly.

src/twisted/mail/_cred.py

@@ -8,6 +8,7 @@ Credential managers for L{twisted.mail}.
 from __future__ import absolute_import, division
 
 import hmac
+import hashlib
 
 from zope.interface import implementer
 
@@ -28,8 +29,8 @@ class CramMD5ClientAuthenticator:
 
 
     def challengeResponse(self, secret, chal):
-        response = hmac.HMAC(secret, chal).hexdigest().encode('ascii')
-        return self.user + b' ' + response
+        response = hmac.HMAC(secret, chal, digestmod=hashlib.md5).hexdigest()
+        return self.user + b' ' + response.encode('ascii')