authentication on NT PDC

Hi,

our company plans to set up a proxy soon and I have some questions:

1. We want to authenticate our users against the NT domain and I found two
   authentication programs which can do this and are included in
   squid2.3.stable3: smb_auth and msntauth. Any suggestions which one would
   be preferable?

2. Some people in our company are concerned about any passwords which may be
   cached by the authentication programs or squid in some file in plain text.
   Are these password cached somewhere (where?) and are they encrypted?

3. Are the user names and passwords encrypted when sent over the network
   (browser --> squid, smb_auth|msntauth --> PDC)?

Thomas

-- 
 The 3 great virtues of a programmer:
 Laziness, Impatience, and Hybris.
                                        --Larry Wall