I have pgp 5.0i installed, and I tried to get it to work
with the new rpm 3.0.2 in RedHat 6.0.  I failed, and after
having looked a bit at the code, I can't understand how it
is supposed to ever work.

In lib/signature there is a function rpmDetectPGPVersion,
which seems to be intended to verify the existense of the
correct pgp version, and to return a path to the binary to
execute.

It looks for both "%_pgpbin" and the same with a "v"
appended.  I assume the intention is to find the command
"pgpv" which is part of PGP 5 but not PGP 2.

But then it first looks for "pgpbin", typically
/usr/bin/pgp, and if it finds it, assumes PGP 2 is
installed.  But "pgp" is normally part of a PGP 5
installation too.  (And only gives an error message if
invoked under that name.)

It isn't strictly necessary to have any command "pgp" when
running PGP 5.  So one could have a non-standard setup with
only the commands pgpv, pgps, pgpk.  If one then sets
"%_pgpbin" to /usr/bin/pgp, and rpmDetectPGPVersion will
correctly detect that PGP 5 is installed.

But that doesn't help much, since it then won't be possible
to call the command in the execlp() call later in the same
file.  There the path, without any "v" appended, is used to
find the command to execute.

And even if it worked, it would be a bit strange to require
such a non-standard installation of pgp.

Rather, I'd suggest to check for PGP 5 first, and then PGP
2.  The patch below implements my fix.  It works fine on my
system.  I haven't tried it on a system with PGP 2, but I
can't imagine how it could fail.  (Which of course might be
a sign of my lack of imagination. :-)

By the way, the comment about "preferring" PGP 2 to PGP 5
seems a bit strange to me.  The word "prefer" seems to
indicate a selection, but the task of the function is to
DETECT which version is installed.  It is not to choose
between them, is it?

*** rpm-3.0.2/lib/signature.c~  Thu Apr 29 21:17:20 1999
--- rpm-3.0.2/lib/signature.c   Fri Aug  6 23:00:43 1999
***************
*** 99,109 ****
        }
        sprintf(pgpvbin, "%sv", pgpbin);

!       /* XXX Prefer pgp-2.6.3 over pgp5 */
!       if (stat(pgpbin, &statbuf) == 0)
!         pgp_version = 26;
!       else if (stat(pgpvbin, &statbuf) == 0)
          pgp_version = 50;
        else
          pgp_version = -1;

--- 99,108 ----
        }
        sprintf(pgpvbin, "%sv", pgpbin);

!       if (stat(pgpvbin, &statbuf) == 0)
          pgp_version = 50;
+       else if (stat(pgpbin, &statbuf) == 0)

+         pgp_version = 26;
        else
          pgp_version = -1;