PGPVERIFY(1)

💅 pgpverify(1) — like, the manual page for pgpverify, bestie

okay so before we even start: this page is from the InterNetNews Documentation girlies, and the whole thing is literally about the pgpverify program. Buckle up, it's giving cryptography but make it cozy 🎀

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✨ NAME ✨

pgpverify — cryptographically verify Usenet control messages. yes bestie, actual crypto, actual signatures, no vibes-based trust 💅

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🌸 SYNOPSIS 🌸

pgpverify [--findid=string] [--test] < message

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🦋 DESCRIPTION 🦋

So pgpverify reads a Usenet control message on standard input — one that's been cryptographically signed using the signcontrol program (or some other program that produces a compatible format, iykyk). Then pgpverify uses a PGP implementation to figure out who signed that control message. Iconic behavior, honestly.

If the control message has a valid signature, pgpverify prints (to stdout) the user ID of the key that signed the message. Otherwise? It dips out with a non-zero exit status. 🫶

If pgpverify is installed as part of INN, it uses INN's configuration to determine:

• what signature verification program to use,
• how to log errors,
• what temporary directory to use,
• and what keyring to use.

Otherwise (no INN around), all of those parameters can be set by editing the beginning of this script. very DIY of it 💜

By default, when running as part of INN, pgpverify expects the PGP key ring to be found in pathetc/pgp — as either pubring.pgp or pubring.gpg, depending on whether PGP or GnuPG is used to verify signatures. If that directory doesn't exist, it will fall back on using the default key ring, which is in a .pgp or .gnupg subdirectory of the running user's home directory. lowkey a glow-down but okay 😭

INN, when using GnuPG, configures pgpverify to use gpg or gpgv, which by default expects keys to be in a keyring named trustedkeys.gpg, since it doesn't implement trust checking directly. pgpverify uses that file if present but falls back to pubring.gpg if it's not found. This bypasses the trust model for checking keys, but is compatible with the way that pgpverify used to behave. Of course, if a keyring is found in pathetc/pgp or configured at the top of the script, that overrides all of this behavior — she said priority, periodt ✨

⚠️ heads up bestie: a few Usenet hierarchies still send control articles signed with old PGP keys using a weak hash algorithm (MD5). Modern versions of GnuPG (2.1.0+) no longer validate such signatures, so you should use GnuPG 1.x or 2.0.x if you need verifying such control articles. not me warning you before you spend three hours debugging 💀

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💖 OPTIONS 💖

• --findid=string — makes pgpverify explicitly search for string in the output from PGP's analysis of the message. Super useful when several UIDs are defined on a single PGP key and the caller to pgpverify needs to check whether a given one is defined on this key. In case the signature is valid but does not contain string, pgpverify exits with exit status 4. rude but fair 🙈
• --test — makes pgpverify print out the input that it is passing to PGP (which is a reconstructed version of the input that supposedly created the control message) as well as the output from PGP's analysis of the message. peek behind the curtain, main character energy 👑

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🌈 EXIT STATUS 🌈

pgpverify may exit with the following statuses:

1. 0 — the control message had a good PGP signature. slay 💅
2. 1 — the control message had no PGP signature.
3. 2 — the control message had an unknown PGP signature.
4. 3 — the control message had a bad PGP signature.
5. 4 — the control message had a good PGP signature but the argument given to the --findid flag had not been found in the output from PGP's analysis of the message.
6. 255 — a problem occurred not directly related to PGP analysis of signature.

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🧚 ENVIRONMENT 🧚

pgpverify does not modify or otherwise alter the environment before invoking the pgp, gpgv or gpg program. Fr fr, it leaves the environment exactly as it found it.

It is the responsibility of the person who installs pgpverify to ensure that when pgp, gpgv or gpg 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. pgpverify can be pointed to an appropriate key ring by editing variables at the beginning of this script. yes you, bestie, you're the one holding the keys 🗝️

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🍓 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, back in the day, David Lawrence 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 audacity 😤

The pgpverify program was designed to allow Usenet news administrators to configure their servers to cryptographically verify control messages 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. like, identity verification but make it cryptographically real 🦋

Thus, appropriate use of the signcontrol and pgpverify programs 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 public key encryption algorithm, which (at least at this time) is believed to be prohibitively difficult for PGP keys of a sufficient bit length. iconic security model, no cap 🔥

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⭐ HISTORY ⭐

pgpverify was written by David C Lawrence <tale@isc.org>. Manual page provided by James Ralston. It is currently maintained by Russ Allbery <eagle@eyrie.org>. legends, all of them 🫶

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👑 COPYRIGHT AND LICENSE 👑

David Lawrence wrote: "Our lawyer told me to include the following. The upshot of it is that you can use the software for free as much as you like." (lawyer-mandated text, but honestly kind of a serve)

Copyright (c) 1996 UUNET Technologies, Inc. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software must display the following acknowledgement:

This product includes software developed by UUNET Technologies, Inc.

4. The name of UUNET Technologies ("UUNET") may not be used to endorse or promote products derived from this software without specific prior written permission.

and now the all-caps part, which I am legally required to keep exactly as-is, so here it is in all its shouty glory 👇

THIS SOFTWARE IS PROVIDED BY UUNET "AS IS" AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
NO EVENT SHALL UUNET BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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💜 SEE ALSO 💜

• gpg(1)
• gpgv(1)
• pgp(1)

<https://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. go follow the source, bestie 🌟

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and that's the whole page, mwah 💋 — this one shipped as INN 2.7.4, dated 2025-03-29, and it's a PGPVERIFY(1) manual page, so now you know the lore. bye bestie, go verify something 🎀