Ubuntu Manpage: gpgv - Verify OpenPGP signatures

Provided by: gpgv_2.2.27-3ubuntu2.4_amd64

NAME

       gpgv - Verify OpenPGP signatures

SYNOPSIS

       gpgv [options] signed_files

DESCRIPTION

       gpgv is an OpenPGP signature verification tool.

       This  program  is  actually  a stripped-down version of gpg which is only able to check signatures. It is
       somewhat smaller than the fully-blown gpg and uses a different (and simpler) way to check that the public
       keys used to make the signature are valid. There are no configuration files and only a  few  options  are
       implemented.

       gpgv  assumes  that  all keys in the keyring are trustworthy.  That does also mean that it does not check
       for expired or revoked keys.

       If no --keyring option is given, gpgv looks for a ``default'' keyring named ‘trustedkeys.kbx’ (preferred)
       or ‘trustedkeys.gpg’ in the home directory of GnuPG, either the default home directory or the one set  by
       the  --homedir  option or the GNUPGHOME environment variable.  If any --keyring option is used, gpgv will
       not look for the default keyring. The --keyring option may be  used  multiple  times  and  all  specified
       keyrings will be used together.

RETURN VALUE

       The  program  returns 0 if everything is fine, 1 if at least one signature was bad, and other error codes
       for fatal errors.

OPTIONS

gpgv recognizes these options:

--verbose
-v Gives more information during processing. If used twice, the input data is listed in detail.

--quiet
-q Try to be as quiet as possible.

--keyring file
Add file to the list of keyrings. If file begins with a tilde and a slash, these are replaced by
the HOME directory. If the filename does not contain a slash, it is assumed to be in the home-
directory ("~/.gnupg" if --homedir is not used).

--output file
-o file
Write output to file; to write to stdout use -. This option can be used to get the signed text
from a cleartext or binary signature; it also works for detached signatures, but in that case this
option is in general not useful. Note that an existing file will be overwritten.

--status-fd n
Write special status strings to the file descriptor n. See the file DETAILS in the documentation
for a listing of them.

--logger-fd n
Write log output to file descriptor n and not to stderr.

--log-file file
Same as --logger-fd, except the logger data is written to file file. Use ‘socket://’ to log to
socket.

--ignore-time-conflict
GnuPG normally checks that the timestamps associated with keys and signatures have plausible
values. However, sometimes a signature seems to be older than the key due to clock problems. This
option turns these checks into warnings.

--homedir dir
Set the name of the home directory to dir. If this option is not used, the home directory defaults
to ‘~/.gnupg’. It is only recognized when given on the command line. It also overrides any home
directory stated through the environment variable ‘GNUPGHOME’ or (on Windows systems) by means of
the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable application. In this case only
this command line option is considered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create an empty file named ‘gpgconf.ctl’
in the same directory as the tool ‘gpgconf.exe’. The root of the installation is then that
directory; or, if ‘gpgconf.exe’ has been installed directly below a directory named ‘bin’, its
parent directory. You also need to make sure that the following directories exist and are
writable: ‘ROOT/home’ for the GnuPG home and ‘ROOT/var/cache/gnupg’ for internal cache files.

--weak-digest name
Treat the specified digest algorithm as weak. Signatures made over weak digests algorithms are
normally rejected. This option can be supplied multiple times if multiple algorithms should be
considered weak. MD5 is always considered weak, and does not need to be listed explicitly.

--enable-special-filenames
This option enables a mode in which filenames of the form ‘-&n’, where n is a non-negative decimal
number, refer to the file descriptor n and not to a file with that name.

EXAMPLES

       gpgv pgpfile
       gpgv sigfile [datafile]
              Verify  the  signature of the file. The second form is used for detached signatures, where sigfile
              is the detached signature (either ASCII-armored or binary) and datafile contains the signed  data;
              if  datafile is "-" the signed data is expected on stdin; if datafile is not given the name of the
              file holding the signed data is constructed by  cutting  off  the  extension  (".asc",  ".sig"  or
              ".sign") from sigfile.

FILES

       ~/.gnupg/trustedkeys.gpg
              The default keyring with the allowed keys.

ENVIRONMENT

       HOME   Used to locate the default home directory.

       GNUPGHOME
              If set directory used instead of "~/.gnupg".