[Taken from http://bugs.debian.org/154283]

A request to provide CRAM-MD5 authentification (in
imaplib).

Logged In: YES 
user_id=163326

Well, the necessary code could probably be found in
smtplib.py. Perhaps it only needs to be adapted.

Logged In: YES 
user_id=6380

Assigning to Piers Lauder, who supports the imaplib module.

But it would be nice if you submitted a patch.

Logged In: YES 
user_id=196212

The support is already present for doing CRAM-MD5
authentication.
For instance the following code should work:

  def authenticator(challenge):
    import hmac
    return User + " " + hamc.HMAC(Password,
challenge).hexdigest()

  M = imaplib.IMAP4(host)
  M.authenticate('CRAM-MD5', authenticator)

Let me know if it works for you, and i'll consider adding
the code to
IMAP4.login to try CRAM-MD5 automatically provided it appears in
the server capabilities response. (I'm reluctant to do so
because similar
code in smtplib failed to work for some SMTP server versions
and broke
login completely.)

Logged In: YES 
user_id=196212

I've added a "login_cram_md5" method to imaplib.py that
performs CRAM-MD5 authentication.

This way users can be certain which authentication method is
in use - they are either getting passwords transmitted in
cleartext if they use "login", or they can try"
login_cram_md5" to attempt the shared-secret style of
authentication.