USENET newsreaders and cryptography: features/suggestions/questions

Hello out there!

	The current version of strn (see below) contains a signature
verification command (control-V).  It looks for either a RIPEM or PGP
signature line and passes the article to the appropriate command for
verification.  (Strn leaves it up to the user to interpret the output
of the command.)

	I have a few questions/requests that I hope the cypherpunks
list can help me with:

	1.  Does anyone know if including code like
system("pgp -m foobar") might cause legal problems?  Strn doesn't
implement any cryptographic techniques.

	2.  What's the status on a USA-legal PGP (using RSAREF)?
I would like to greatly expand strn's cryptographic features, but I'd
rather not implement features that many of strn's users can't use.
(That includes me--I won't use PGP until/unless the legal issues are
 cleared up.)

	3.  It would be greatly convenient if someone would implement
a "verify signature only" switch for PGP.  Most of the applications I
would like to use don't involve data hiding--just signature verification.
I'm also lobbying the RIPEM author to include a similar feature.

	Also, if anyone has any comments or suggestions about
newsreader cryptographic features feel free to send mail.  I hope to
do some work later with things like remote reconfiguration, trusted
ratings, suggested reading lists, and the like.

				--Cliff

P.S.  Strn is about 10K lines of C code added to trn.  It is
(probably) just a few weeks away from a public beta test.  If anyone
really wants to test strn, let me know and I'll consider it.  More
information is also available via finger or mail.

-- 
Clifford A. Adams  caadams@polaris.unm.edu | USENET Interface Project:
457 Ash St. NE      Albuquerque, NM  87106 | Tools for advanced newsreading
STRN (Scan TRN) now in testing: trn 3.0 plus flexible newsgroup menus, fast
article scoring with score ordered display, and merged/virtual newsgroups.

In message <9307080348.AA10446@polaris.unm.edu>, Clifford A Adams writes:
> 	1.  Does anyone know if including code like
> system("pgp -m foobar") might cause legal problems?  Strn doesn't
> implement any cryptographic techniques.
	I wouldn't know, but to stay completely safe, it *might* be a good
idea to use environment variables.

CRYPTOPROGRAM=pgp

system(strcat(getenv("CRYPTOPROGRAM"), " -m foobar"))

	(I'm not well-versed in strcat, so this could be wrong, but you
know what I mean.)
	Then you're not mentioning PGP at all in the code. (Env. variables
for the options would be a good idea as well.. that way you can't be
attacked under the premise, "It's OBVIOUSLY for PGP, because the options
are PGP-options.")
 

> 	3.  It would be greatly convenient if someone would implement
> a "verify signature only" switch for PGP.  Most of the applications I
> would like to use don't involve data hiding--just signature verification.
> I'm also lobbying the RIPEM author to include a similar feature.
	One feature I'd like would be easy to parse PGP output. That way PGP
can be more easily integrated with other programs. For example, doing
the following:

(-p for "easyparse"?)
pgp -p <signed.txt

	Would create output to stderr:

3434/344D
Sameer Parekh <zane@genesis.mcs.com>
01/01/93 12:34:56 GMT

	Then a program can parse it very easily. A successful sig would give
a return code of 0, and failed sig would have a nonzero return code. 

--
| Sameer Parekh-zane@genesis.MCS.COM-PFA related mail to pfa@genesis.MCS.COM |
| Apprentice Philosopher, Writer, Physicist, Healer, Programmer, Lover, more |
| "Symbiosis is Good" - Me_"Specialization is for Insects" - R. A. Heinlein_/
 \_______________________/ \______________________________________________/

In message <9307080348.AA10446@polaris.unm.edu>, Clifford A Adams writes:
> 	1.  Does anyone know if including code like
> system("pgp -m foobar") might cause legal problems?  Strn doesn't
> implement any cryptographic techniques.
	I wouldn't know, but to stay completely safe, it *might* be a good
idea to use environment variables.

CRYPTOPROGRAM=pgp

system(strcat(getenv("CRYPTOPROGRAM"), " -m foobar"))

	(I'm not well-versed in strcat, so this could be wrong, but you
know what I mean.)
	Then you're not mentioning PGP at all in the code. (Env. variables
for the options would be a good idea as well.. that way you can't be
attacked under the premise, "It's OBVIOUSLY for PGP, because the options
are PGP-options.")
 

> 	3.  It would be greatly convenient if someone would implement
> a "verify signature only" switch for PGP.  Most of the applications I
> would like to use don't involve data hiding--just signature verification.
> I'm also lobbying the RIPEM author to include a similar feature.
	One feature I'd like would be easy to parse PGP output. That way PGP
can be more easily integrated with other programs. For example, doing
the following:

(-p for "easyparse"?)
pgp -p <signed.txt

	Would create output to stderr:

3434/344D
Sameer Parekh <zane@genesis.mcs.com>
01/01/93 12:34:56 GMT

	Then a program can parse it very easily. A successful sig would give
a return code of 0, and failed sig would have a nonzero return code. 

--
| Sameer Parekh-zane@genesis.MCS.COM-PFA related mail to pfa@genesis.MCS.COM |
| Apprentice Philosopher, Writer, Physicist, Healer, Programmer, Lover, more |
| "Symbiosis is Good" - Me_"Specialization is for Insects" - R. A. Heinlein_/
 \_______________________/ \______________________________________________/

On Thu, 8 Jul 1993, Sameer wrote:

> CRYPTOPROGRAM=pgp
> 
> system(strcat(getenv("CRYPTOPROGRAM"), " -m foobar"))
> 
> 	(I'm not well-versed in strcat, so this could be wrong, but you
> know what I mean.)

I know you put a disclaimer, but I'll warn you that the above code is very
dangerous...  strcat() concatenates to its first argument, and the value
returned by getenv is not a suitable argument in this case...  the fix:

char enccmd[100];
strcpy(enccmd, getenv("CRYPTOPROGRAM"));
strcat(enccmd, " -m foobar");
system(enccmd);

However, I still find this unsatisfying, as the'-m' is probably a PGP
sepcific option, and it seems to me that a more general solution would be
either some form of template in the environment variable:

CRYPTOPROGRAM="pgp encode=-e decode= sign=-s stdin=-f text=-t ascii=-a
conventional=-c userid=-u %u forcepager=-m pagemode=-m wipeorig=-w
recoverorigfilename=-p detatchsig=-b leavesigintact=-d adresseelist=%a
...and so on..."

or a set of environment variables, such as:

CRYPTOENCODE=
CRYPTODECODE=
CRYPTOSIGN=
CRYPTOVERIFYSIGNATURE=
...and so on...

Either way is a lot more work, but probably a lot more general as well...
This is a piece of code that only needs to be written once...  would take
more work to do the documentation that the code...  Any takers, or should I
put this on my TODO list as well?

--
Nick MacDonald               | NMD on IRC
i6t4@jupiter.sun.csd.unb.ca  | PGP 2.1 Public key available via finger
i6t4@unb.ca                  | (506) 457-1931    ^{1024/746EBB 1993/02/23}