From: bunte@neocad.com (Dave Bunte)
Subject: PGP server offers full two way encription
Organization: NeoCAD, Inc.
X-Newsreader: TIN [version 1.1 PL8]
Date: Tue, 22 Dec 1992 20:22:44 GMT

[ Article crossposted from alt.drugs ]
[ Author was  ]
[ Posted on Sat, 19 Dec 1992 23:42:22 GMT ]


| PAX - Public Access Unix (Adelaide,South Australia) - Anonymous Posting Host
| ============================================================================
|
|Last modified: Fri Nov 20 18:55:52 CST 1992
|
| Information about Anonymous & Privacy-Enhanced Posting.
| =======================================================
|
|PAX is conducting research into the viability of anonymous privacy-
|enhanced mail as a means of providing practical, secure and confidential
|electronic mail and news. An experimental server has been setup and
|you are encouraged to use it.
|
|There are many anonymous posting services in existence which provide
|anonymous electronic mail and posting to specific newsgroups where
|posting is sometimes harmful to one's health or reputation ! Such
|services allow you to:
|
| - post anonymously to those news groups
|
| - reply anonymously to posts by email
|
| - converse anonymously with another anonymous user, neither of
|   you knowing your real identities
|
|Privacy-enhanced electronic mail refers to the concept of encrypting
|one's mail prior to sending it off into the ether, presumably to
|someone at the other end capable of decrypting it. If one uses a
|so-called "public key" method of encryption, then one can make one's
|"public" key widely known so that anyone can encrypt mail to you, but only
|you can decrypt it using your "secret" key. There is much development
|going on in this area, but one quite popular public-domain implementation
|is Philip Zimmermann's "Pretty Good Privacy 2.0" which makes use of a
|number of cryptographic methods including the RSA algorithm in places
|(See Legal Issues later on). PGP allows you to:
|
| - exchange public keys with another individual
|
| - encode messages to them that only they can read
|
| - receive messages from them that only you can read
|
|These tools are all very well for the specific purposes for which they
|were designed, but unfortunately your anonymous message or post is not
|actually anonymous until it gets to the machine that host's the service.
|Anyone in between, including your own administrators, can in theory
|read your post, even though they won't know to whom it is directed. What
|is more they can also read replies addressed back to you. This can be
|highly embarrassing at best, and result in dismissal or disconnection
|at worst if your thoughts, beliefs or activities are disapproved of by
|the powers that be, even if they are perfectly legal.
|
|PAX's privacy-enhanced anonymous services were conceived in the belief
|that free speech and privacy are fundamental rights and that it is
|high time the networks to which we are connected provided such services
|on a routine basis. Seeing as they don't we have to make a start somewhere.
|
|This service provides:
|
| - conventional anonymous mailing and posting services via a "normal"
|   alias assigned in the usual fashion
|
| - the ability to post to ANY newsgroup that is carried out of PAX
|   (which includes most non-regional groups)
|
| - PGP 2.0 based privacy-enhanced mail & posting, including:
|
|   - ability to register your "public" key with PAX, so that PAX
|     can send encrypted messages to you
|
|   - local generation of a unique public key which is sent to you,
|     so that you can send encrypted messages to PAX
|
|   - any encoded messages from you mailed to a user or newsgroup are
|     decrypted at PAX before being passed on in anonymous form
|
|   - any anonymous replies to your "pgp" alias are encrypted before
|     being mailed to you
|
|For example, once you have obtained your PGP 2.0 software (as described
|later) and got it going, and once you have generated and registered
|your public key and received PAX's key in response, you will be able
|to post to any newsgroup without anyone beyond your machine having
|access to the plaintext of your post.
|
|Furthermore, if another user has registered in the same manner, and
|you know their anonymous alias or are responding to one of their
|anonymous posts, even though you don't know who they are and haven't
|exchanged keys to communicate directly, the PAX service will automatically
|decrypt any encrypted messages from you and re-encrypt them before
|passing them on to the other person !
|
| How to use it.
| ==============
|
|All transactions are handled by email, and commands are selected by
|the name of the alias to which you mail, not by the subject or body
|of the message (which are ignored unless sending or posting a message).
|The separator between the "anon" and the command is a dot (period,'.')
|and nothing else will work ! Not '-', not '_', not ":", only a dot.
|
|The site to address mail is "pax.tpa.com.au". If this fails for some
|reason, you may need to address it to the specific host (at present)
|ie. "flash.pax.tpa.com.au".
|
|"Normal" (unencrypted) commands:
|
| - To get information (this message):
|
|    mail anon.info@pax.tpa.com.au
|
| - To see what your "normal" alias is, or get one:
|
|    mail anon.ping@pax.tpa.com.au
|
| - To send a reply to another anonymous user:
|
|    mail anon.###@pax.tpa.com.au
|
|    NB:
|      - eg. mail anon.36@pax.tpa.com.au
|
|      - don't be creative ... anon.036 won't work
|
|      - an attempt is made to strip off signature lines by discarding
|        everything after a line starting with "--" or "__"
|
| - To send a post to a newsgroup:
|
|    mail anon.post.groupname@pax.tpa.com.au
|
|    NB:
|      - eg. "mail anon.post.talk.abortion" will send a
|        post to "talk.abortion"
|
|      - only the Subject field from your post is used, the rest of
|        the header is discarded
|
|      - the newsgroup is selected by the alias; Newsgroup header
|        fields are discarded; hence cross-posting isn't feasible
|
|      - signatures are stripped as above
|
|"PGP" (encryption) commands:
|
| - To register your public key with PAX: (ABSOLUTELY NECESSARY)
|
|    mail anon.key@pax.tpa.com.au
|
|    NB:
|      - first you have to make install pgp and make a key then send it
|        in a "anon.key" command
|
|      - the body of the message MUST contain an ascii encoded public key
|        generated by PGP V2.0. You may use your regular public key that
|        you give to other people if you wish. The user ID name must be
|        unlikely to conflict with one PAX already has, so use your full
|        name, or include your email address or something. If you want
|        you can use a unique key just for PAX - it makes no difference.
|        If PAX already has a key of the same user-id it will reject yours.
|        Note that this means that you need different key user-id's on
|        different machines (or mail addresses anyway).
|
|        # makes new keys & adds to your "keyring"
|        pgp -kg
|        Enter a user ID for your public key: First M. Last of somefirm
|
|        # extract key in ascii form suitable for a message body
|        pgp -kxa "First M. Last of somefirm" savedfile pubring
|
|        # send it to PAX
|        mail anon.key@pax.tpa.com.au <savedfile.asc
|
|      - PAX will respond by sending you a new alias number and a
|        public key to add to your keyring to use to encrypt messages
|        to PAX. It will have a user ID name of "paxanon.publickey"
|        and you should add it to your public key ring by saving the
|        message in a file and presenting it as follows:
|
|        pgp -ka savedfile
|
|        Your life will be easier in future if you reply yes to the
|        certify question.
|
|      - Note that now you may have two aliases, that sent in response to
|        the anon.key command and that sent in response to the anon.ping
|        command or previous unencrypted replies or posts. Any sunsequent
|        replies or posts that you encrypt before sending will be seen
|        to others as having come from the new alias, and replies will be
|        encrypted before being passed on to you. Any plaintext messages
|        you send will appear to have come from the original alias and
|        responses will also come back in plaintext.
|
| - Sending encrypted posts and replies.
|
|     There are no other commands. If you encrypt a message and send it
|     using the "anon.reply" and "anon.post" groups, the software will
|     detect that they are encrypted, select the appropriate alias as
|     a return address, decrypt the message, and mail or post it.
|
|     You should use PGP 2.0 to encrypt messages sent to PAX, using
|     the public key that PAX sent to you. DON'T FORGET TO SIGN your
|     message using the secret key corresponding to the public key
|     that you sent to PAX !!! Unsigned messages will be rejected
|     to ensure that the message is really from you and not someone
|     pretending to be you using your account or mailpath.
|
|     Eg.:
|
|        # sign and encrypt message for mailing to pax.
|        pgp -east message "paxanon.publickey" -u "First M. Last of somefirm"
|        mail -s "A test post" anon.post.alt.test <message.asc
|
|     Note the -a (armor) and -t (text) options. Note also the subject
|     flag to mail - PAX will whinge if you post something without a
|     subject.
|
|     Similarly, all messages to you will be signed using PAX's secret
|     key corresponding to the public key PAX sent to you, hence you
|     will know if the message really came from PAX and not someone
|     else using your public key.
|
|     ***** NB. The ENTIRE encrypted segment will be passed on after
|     it has been decrypted. There is no processing of any contained
|     header (though it won't work as a header), nor any removal of
|     signature information within the encrypted text. Take great care
|     to ensure that there is no identifying information within the
|     encrypted text. *****
|
|     Any plain text accompanying the encrypted text will be discarded.
|     The Subject header field is still passed on during postings as
|     with "normal" unencrypted posts.
|
|     More work may be done on these "features" if there is sufficient
|     demand for it :).
|
|Miscellaneous administrative commands:
|
| - To see the current status of the system (message of the day):
|
|    mail anon.status@pax.tpa.com.au
|
| - To send mail to a human administrator:
|
|    mail anon.admin@pax.tpa.com.au
|
| Mailing List
| ============
|
|To send mail to/join/unjoin a mailing list about this service, and
|anonymous services in general:
|
|    mail anon.list@pax.tpa.com.au
|    mail anon.subscribe@pax.tpa.com.au
|    mail anon.unsubscribe@pax.tpa.com.au
|
|
| How secure is it ?
| ==================
|
|Not bad. Clearly it depends on the security of the underlying PGP 2.0
|software which is discussed at length in its documentation.
|
|The keys are stored, and the messages encrypted and decrypted on
|a server which also hosts a Public Access Unix system. These files
|are protected by the usual Unix security mechanisms, but in the
|event of a security breach could conceivably become visible. The
|keys would hence be compromised and any messages passing through
|could be decrypted. The PAX administration could theoretically
|access the keys and files at will of course.
|
|It is hard to conceive of an alternative implementation which links
|anonymity with privacy enhancement however. This is no substitute for
|a direct person to person link with certified keys and this service
|should not be used as a substitute for such if security is a primary
|concern.
|
| Legal Issues.
| =============
|
|PGP 2.0's use of the RSA algorithm is a problem in the US where a patent
|is now held on the algorithm, despite its widespread promulgation before
|the patent was obtained. The PGP documentation discusses this issue at
|length.
|
|Sufficeth to say, this service is provided by a site in Australia and
|hence should not be subject to the constraints imposed by the US patent.
|The service is offered to anyone who can reach this site by mail, in
|addition to PAX's own users, and there is no intention of obtaining any
|commercial gain by providing the privacy-enhanced anonymous service.
|
|Whether individuals in the US can legally use the PGP software to use the
|service provided by PAX for their own personal use, without first obtaining
|a license to use the RSA algorithm is an untested issue. Certainly the
|software is widely available even though it is now maintained outside the
|US.
|
|No such concerns should apply anywhere other than the US.
|
|This project is an experiment to see if the concept is feasible and if
|there is any demand for it. The software is crude, but functional,
|but it is quite possible that it will fail in unforeseen circumstances.
|It is designed to loose or fail to pass on a message rather than post or
|return plaintext (which would be very undesirable) but there can be no
|guarantees. It is conceivable that plaintext might get sent where it
|was not intended, and PAX assumes no responsibility for the consequences.
|At least this would be no worse than the situation that prevails with
|current anonymous services.
|
|THIS IS EXPERIMENTAL SOFTWARE IN A STATE OF FLUX - YOU HAVE BEEN WARNED.
|
|END OF FILE
|
|- --
|** Anonymity & Privacy by PAX - Public Access Unix (Adelaide,South Australia)
**
|anon.admin@pax.tpa.com.au (a human)    anon.info@pax.tpa.com.au   (for help)
|anon.ping@pax.tpa.com.au  (get alias)  anon.key@pax.tpa.com.au    (register
key)
|anon.###@pax.tpa.com.au   (reply)      anon.post.g@pax.tpa.com.au (post to g)
|anon.list@pax.tpa.com.au  (to mailing list)
|anon.subscribe@pax.tpa.com.au          anon.unsubscribe@pax.tpa.com.au
|
|For dialup Unix access phone +61-8-235-9010 - online registration.
-------------------------------------------------------------------------
To find out more about the anon service, send mail to help@anon.penet.fi.
Due to the double-blind system, any replies to this message will be anonymized,
and an anonymous id will be allocated automatically. You have been warned.
-- 
The author makes no representations about the suitability of these
opinions for any purpose.  They are provided "as is" without express
or implied warranty...

Newsgroups: sci.crypt