1.\" $NetBSD: netpgpverify.1,v 1.13 2018/04/04 21:39:35 sevan Exp $
2.\"
3.\" Copyright (c) 2013,2014,2015 Alistair Crooks <agc@NetBSD.org>
4.\" All rights reserved.
5.\"
6.\" Redistribution and use in source and binary forms, with or without
7.\" modification, are permitted provided that the following conditions
8.\" are met:
9.\" 1. Redistributions of source code must retain the above copyright
10.\"    notice, this list of conditions and the following disclaimer.
11.\" 2. Redistributions in binary form must reproduce the above copyright
12.\"    notice, this list of conditions and the following disclaimer in the
13.\"    documentation and/or other materials provided with the distribution.
14.\"
15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25.\"
26.Dd April 3, 2018
27.Dt NETPGPVERIFY 1
28.Os
29.Sh NAME
30.Nm netpgpverify
31.Nd standalone program for digital signature verification
32.Sh SYNOPSIS
33.Nm
34.Op Fl v
35.Op Fl S Ar ssh-pub-key-file
36.Op Fl c Ar command
37.Op Fl k Ar keyring
38.Ar file ...
39.Sh DESCRIPTION
40The
41.Nm
42implements digital signature verification.
43It is designed to be simple and standalone; no external libraries, except
44for
45.Xr libz
46and
47.Xr libbz2
48are used, in order to ensure maximum portability.
49.Pp
50It is completely rewritten from the version of the program that appeared in
51.Nx 6.0
52as part of the
53.Xr netpgp 1
54suite of commands.
55.Pp
56The
57.Nm
58utility requires a file containing public keys, commonly called a
59.Dq keyring .
60Digitally-signed information can be fed to
61.Nm
62in two ways: as standard input, or as files provided on the command line.
63The public key part of the key which was used to sign the file must be
64present, or the signature verification will fail.
65Files may be signed in two distinct ways: as text documents, and as binary
66files.
67Text documents modify the contents to add different line-ending
68characters, and behave differently at the final byte of the input document.
69Binary files are read verbatim, and are not modified in any way.
70.Pp
71The
72.Fl k
73command line argument allows a keyring to be specified.
74.Pp
75The
76.Fl v
77command line argument prints the version of the
78.Nm
79command and then exits.
80.Pp
81The
82.Fl c
83argument allows a
84.Dq command
85to be given, modifying the behaviour of the
86.Nm
87command.
88This command can take one of three values:
89.Dq verify
90which is also the default, which verifies the signature
91on the data;
92.Dq cat
93will also verify the signature on the data, and, if
94successfully verified, will display the verified
95data on
96.Dv stdout ;
97and
98.Dq dump
99which will dump the individual PGP packets to standard out, along
100with a hexadecimal dump of the first part of the contents of each
101packet.
102Please note that the packets from the public key ring will also be dumped
103using this command.
104The key ring packets will be displayed immediately before the packets in the
105file being verified.
106.Pp
107The
108.Fl S
109argument allows an ssh public key file to be used as the source of
110truth for the key.
111This ssh-key-based signature can be created using the
112.Xr netpgp 1
113utility.
114.Pp
115If a detached signature
116.Dq .sig
117is given on the command line, the signing information will be retrieved
118from that file, and the original data is expected to be found in a file in the same
119directory with the same name with the
120.Dq .sig
121suffix removed.
122.Pp
123Both text mode signatures, and binary signatures, can be verified by
124.Nm
125.Sh SIGNING AND VERIFICATION
126Verification of a file's signature is best viewed using the following example:
127.Bd -literal
128% netpgpverify -k pubring.gpg NetBSD-6.0_RC1_hashes.asc
129Good signature for NetBSD-6.0_RC1_hashes.asc made Thu Aug 23 11:47:50 2012
130signature     4096/RSA (Encrypt or Sign) 064973ac4c4a706e 2009-06-23
131fingerprint   ddee 2bdb 9c98 a0d1 d4fb dbf7 0649 73ac 4c4a 706e
132uid           NetBSD Security Officer <security-officer@NetBSD.org>
133%
134.Ed
135.Sh EXIT STATUS
136The
137.Nm
138utility will return 0 for a successful verification,
1391 if the file's signature does not match what was expected,
140or 2 if any other error occurs.
141.Sh SEE ALSO
142.Xr netpgp 1 ,
143.\" .Xr libbz2 3 ,
144.Xr zlib 3
145.Sh STANDARDS
146.Rs
147.%A J. Callas
148.%A L. Donnerhacke
149.%A H. Finney
150.%A D. Shaw
151.%A R. Thayer
152.%D November 2007
153.%R RFC 4880
154.%T OpenPGP Message Format
155.Re
156.Sh HISTORY
157The
158.Nm
159command first appeared in
160.Nx 7.0 .
161.Sh AUTHORS
162.An Alistair Crooks Aq agc@NetBSD.org .
163