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

NAME

       pgpverify - cryptographically verify Usenet control messages

SYNOPSIS

       pgpverify [ -test ]

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 ``-test'' flag causes pgpverify to print out the input it is passing to pgp (which is a reconstructed version of the input that suppos-
       edly created the control message) as well as the output of pgp's analysis of the message.

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)