pgpverify(8)						      System Manager's Manual						      pgpverify(8)

NAME

       pgpverify - cryptographically verify Usenet control messages

SYNOPSIS

       pgpverify

DESCRIPTION

       The  pgpverify program reads (on standard input) a Usenet control message that has been cryptographically signed using the signcontrol pro-
       gram.  pgpverify then uses the pgp program to determine who signed the control message.	If the control message was validly signed, pgpver-
       ify outputs (to stdout) the User ID of the key ID that signed the message.

OPTIONS

       The pgpverify program takes no options.

EXIT STATUS

       pgpverify returns the follow exit statuses for the following cases:

       0      The control message had a good PGP signature.

       1      The control message had no PGP signature.

       2      The control message had an unknown PGP signature.

       3      The control message had a bad PGP signature.

       255    A problem occurred not directly related to PGP analysis of signature.

AUTHOR

       David C Lawrence <tale@isc.org>

ENVIRONMENT

       pgpverify  does	not modify or otherwise alter the environment before invoking the pgp program.	It is the responsibility of the person who
       installs pgpverify to ensure that when pgp runs, it has the ability to locate and read a PGP key file that contains the PGP public keys for
       the appropriate Usenet hierarchy administrators.

SEE ALSO

       pgp(1)

NOTES

       Historically,  Usenet news server administrators have configured their news servers to automatically honor Usenet control messages based on
       the originator of the control messages and the hierarchies for which the control messages applied.  For	example,  in  the  past,  David  C
       Lawrence  <tale@uunet.uu.net>  always  issued  control  messages  for the "Big 8" hierarchies (comp, humanities, misc, news, rec, sci, soc,
       talk).  Usenet news administrators would configure their news server software to automatically honor newgroup and rmgroup control  messages
       that originated from David Lawrence and applied to any of the Big 8 hierarchies.

       Unfortunately,  Usenet news articles (including control messages) are notoriously easy to forge.  Soon, malicious users realized they could
       create or remove (at least temporarily) any Big 8 newsgroup they  wanted  by  simply  forging  an  appropriate  control	message  in  David
       Lawrence's name.  As Usenet became more widely used, forgeries became more common.

       The  pgpverify program was designed to allow Usenet news administrators to configure their servers to cryptographically verify control mes-
       sages before automatically acting on them.  Under the pgpverify system, a Usenet hierarchy maintainer creates a PGP public/private key pair
       and  disseminates  the public key.  Whenever the hierarchy maintainer issues a control message, he uses the signcontrol program to sign the
       control message with the PGP private key.  Usenet news administrators configure their news servers to run  the  pgpverify  program  on  the
       appropriate  control  messages, and take action based on the PGP key User ID that signed the control message, not the name and address that
       appear in the control message's From or Sender headers.

       Thus, using the signcontrol and pgpverify programs appropriately essentially eliminates the possibility of malicious users  forging  Usenet
       control	messages that sites will act upon, as such users would have to obtain the PGP private key in order to forge a control message that
       would pass the cryptographic verification step.	If the hierarchy administrators properly protect their PGP private keys, the  only  way  a
       malicious  user	could  forge  a  validly-signed control message would be by breaking the RSA encryption algorithm, which (at least at this
       time) is believed to be an NP-complete problem.	If this is indeed the case, discovering the PGP private key based on the PGP public key is
       computationally impossible for PGP keys of a sufficient bit length.

       <URL:ftp://ftp.isc.org/pub/pgpcontrol/>	is  where  the	most recent versions of signcontrol and pgpverify live, along with PGP public keys
       used for hierarchy administration.

																      pgpverify(8)