I'd like to authenticate my PB client against a hashed password file, but I'm getting an error when I use a hash: Failure: twisted.cred.error.UnhandledCredentials: No checker for twisted.spread.interfaces.IJellyable, twisted.cred.credentials.IUsernameHashedPassword, twisted.cred.credentials.ICredentials, twisted.spread.pb.IUsernameMD5Password However, if I use plaintext passwords, it works fine. I'm working with the example in the book: http://twistedmatrix.com/documents/current/howto/pb-cred#auto7 with the credential checker set to import sha myChecker = checkers.FilePasswordDB("my_hashed_passwd_file", hash = lambda u, p, h: sha.new(p).hexdigest()) I've tested this checker and hash, and they work fine for logging in to my nevow site. The example works, though if I use plaintext passwords and don't pass in a hash: myPlaintextChecker = checkers.FilePasswordDB("my_plaintext_passwd_file") Thanks for any hints, Dave Cook