GNU Privacy Guard GPG2(1)
NAME
gpg2 - OpenPGP encryption and signing tool
SYNOPSIS
gpg2 [--homedir dir] [--options file] [options] command
[args]
DESCRIPTION
gpg2 is the OpenPGP part of the GNU Privacy Guard (GnuPG).
It is a tool to provide digital encryption and signing ser-
vices using the OpenPGP standard. gpg2 features complete key
management and all bells and whistles you can expect from a
decent OpenPGP implementation.
In contrast to the standalone version gpg, which is more
suited for server and embedded platforms, this version is
installed under the name gpg2 and more targeted to the desk-
top as it requires several other modules to be installed.
The standalone version will be kept maintained and it is
possible to install both versions on the same system. If
you need to use different configuration files, you should
make use of something like gpg.conf-2 instead of just
gpg.conf.
RETURN VALUE
The program returns 0 if everything was fine, 1 if at least
a signature was bad, and other error codes for fatal errors.
WARNINGS
Use a *good* password for your user account and a *good*
passphrase to protect your secret key. This passphrase is
the weakest part of the whole system. Programs to do dic-
tionary attacks on your secret keyring are very easy to
write and so you should protect your "~/.gnupg/" directory
very well.
Keep in mind that, if this program is used over a network
(telnet), it is *very* easy to spy out your passphrase!
If you are going to verify detached signatures, make sure
that the program knows about it; either give both filenames
on the command line or use - to specify STDIN.
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INTEROPERABILITY
GnuPG tries to be a very flexible implementation of the
OpenPGP standard. In particular, GnuPG implements many of
the optional parts of the standard, such as the SHA-512
hash, and the ZLIB and BZIP2 compression algorithms. It is
important to be aware that not all OpenPGP programs imple-
ment these optional algorithms and that by forcing their use
via the --cipher-algo, --digest-algo, --cert-digest-algo, or
--compress-algo options in GnuPG, it is possible to create a
perfectly valid OpenPGP message, but one that cannot be read
by the intended recipient.
There are dozens of variations of OpenPGP programs avail-
able, and each supports a slightly different subset of these
optional algorithms. For example, until recently, no
(unhacked) version of PGP supported the BLOWFISH cipher
algorithm. A message using BLOWFISH simply could not be read
by a PGP user. By default, GnuPG uses the standard OpenPGP
preferences system that will always do the right thing and
create messages that are usable by all recipients, regard-
less of which OpenPGP program they use. Only override this
safe default if you really know what you are doing.
If you absolutely must override the safe default, or if the
preferences on a given key are invalid for some reason, you
are far better off using the --pgp6, --pgp7, or --pgp8
options. These options are safe as they do not force any
particular algorithms in violation of OpenPGP, but rather
reduce the available algorithms to a "PGP-safe" list.
COMMANDS
Commands are not distinguished from options except for the
fact that only one command is allowed.
gpg2 may be run with no commands, in which case it will per-
form a reasonable action depending on the type of file it is
given as input (an encrypted message is decrypted, a signa-
ture is verified, a file containing keys is listed).
Please remember that option as well as command parsing stops
as soon as a non-option is encountered, you can explicitly
stop parsing by using the special option --.
Commands not specific to the function
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--version
Print the program version and licensing information.
Note that you cannot abbreviate this command.
--help
-h Print a usage message summarizing the most useful com-
mand line options. Note that you cannot abbreviate
this command.
--warranty
Print warranty information.
--dump-options
Print a list of all available options and commands.
Note that you cannot abbreviate this command.
Commands to select the type of
--sign
-s Make a signature. This command may be combined with --
encrypt (for a signed and encrypted message), --
symmetric (for a signed and symmetrically encrypted
message), or --encrypt and --symmetric together (for a
signed message that may be decrypted via a secret key
or a passphrase). The key to be used for signing is
chosen by default or can be set with the --local-user
and --default-key options.
--clearsign
Make a clear text signature. The content in a clear
text signature is readable without any special
software. OpenPGP software is only needed to verify the
signature. Clear text signatures may modify end-of-
line whitespace for platform independence and are not
intended to be reversible. The key to be used for
signing is chosen by default or can be set with the --
local-user and --default-key options.
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--detach-sign
-b Make a detached signature.
--encrypt
-e Encrypt data. This option may be combined with --sign
(for a signed and encrypted message), --symmetric (for
a message that may be decrypted via a secret key or a
passphrase), or --sign and --symmetric together (for a
signed message that may be decrypted via a secret key
or a passphrase).
--symmetric
-c Encrypt with a symmetric cipher using a passphrase. The
default symmetric cipher used is CAST5, but may be
chosen with the --cipher-algo option. This option may
be combined with --sign (for a signed and symmetrically
encrypted message), --encrypt (for a message that may
be decrypted via a secret key or a passphrase), or --
sign and --encrypt together (for a signed message that
may be decrypted via a secret key or a passphrase).
--store
Store only (make a simple RFC1991 literal data packet).
--decrypt
-d Decrypt the file given on the command line (or STDIN if
no file is specified) and write it to STDOUT (or the
file specified with --output). If the decrypted file is
signed, the signature is also verified. This command
differs from the default operation, as it never writes
to the filename which is included in the file and it
rejects files which don't begin with an encrypted mes-
sage.
--verify
Assume that the first argument is a signed file or a
detached signature and verify it without generating any
output. With no arguments, the signature packet is read
from STDIN. If only a sigfile is given, it may be a
complete signature or a detached signature, in which
case the signed stuff is expected in a file without the
".sig" or ".asc" extension. With more than 1 argument,
the first should be a detached signature and the
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remaining files are the signed stuff. To read the
signed stuff from STDIN, use - as the second filename.
For security reasons a detached signature cannot read
the signed material from STDIN without denoting it in
the above way.
--multifile
This modifies certain other commands to accept multiple
files for processing on the command line or read from
STDIN with each filename on a separate line. This
allows for many files to be processed at once. --
multifile may currently be used along with --verify,
--encrypt, and --decrypt. Note that --multifile --
verify may not be used with detached signatures.
--verify-files
Identical to --multifile --verify.
--encrypt-files
Identical to --multifile --encrypt.
--decrypt-files
Identical to --multifile --decrypt.
--list-keys
-k
--list-public-keys
List all keys from the public keyrings, or just the
keys given on the command line.
Avoid using the output of this command in scripts or
other programs as it is likely to change as GnuPG
changes. See --with-colons for a machine-parseable key
listing command that is appropriate for use in scripts
and other programs.
--list-secret-keys
-K List all keys from the secret keyrings, or just the
ones given on the command line. A # after the letters
sec means that the secret key is not usable (for exam-
ple, if it was created via --export-secret-subkeys).
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--list-sigs
Same as --list-keys, but the signatures are listed too.
This command has the same effect as using --list-keys
with --with-sig-list.
For each signature listed, there are several flags in
between the "sig" tag and keyid. These flags give addi-
tional information about each signature. From left to
right, they are the numbers 1-3 for certificate check
level (see --ask-cert-level), "L" for a local or non-
exportable signature (see --lsign-key), "R" for a non-
Revocable signature (see the --edit-key command
"nrsign"), "P" for a signature that contains a policy
URL (see --cert-policy-url), "N" for a signature that
contains a notation (see --cert-notation), "X" for an
eXpired signature (see --ask-cert-expire), and the
numbers 1-9 or "T" for 10 and above to indicate trust
signature levels (see the --edit-key command "tsign").
--check-sigs
Same as --list-sigs, but the signatures are verified.
Note that for performance reasons the revocation status
of a signing key is not shown. This command has the
same effect as using --list-keys with --with-sig-check.
The status of the verification is indicated by a flag
directly following the "sig" tag (and thus before the
flags described above for --list-sigs). A "!" indi-
cates that the signature has been successfully veri-
fied, a "-" denotes a bad signature and a "%" is used
if an error occurred while checking the signature (e.g.
a non supported algorithm).
--locate-keys
Locate the keys given as arguments. This command basi-
cally uses the same algorithm as used when locating
keys for encryption or signing and may thus be used to
see what keys gpg2 might use. In particular external
methods as defined by --auto-key-locate may be used to
locate a key. Only public keys are listed.
--fingerprint
List all keys (or the specified ones) along with their
fingerprints. This is the same output as --list-keys
but with the additional output of a line with the
fingerprint. May also be combined with --list-sigs or
--check-sigs. If this command is given twice, the
fingerprints of all secondary keys are listed too.
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--list-packets
List only the sequence of packets. This is mainly use-
ful for debugging.
--card-edit
Present a menu to work with a smartcard. The subcommand
"help" provides an overview on available commands. For
a detailed description, please see the Card HOWTO at
http://www.gnupg.org/documentation/howtos.html#GnuPG-
cardHOWTO .
--card-status
Show the content of the smart card.
--change-pin
Present a menu to allow changing the PIN of a
smartcard. This functionality is also available as the
subcommand "passwd" with the --card-edit command.
--delete-key name
Remove key from the public keyring. In batch mode
either --yes is required or the key must be specified
by fingerprint. This is a safeguard against accidental
deletion of multiple keys.
--delete-secret-key name
Remove key from the secret and public keyring. In batch
mode the key must be specified by fingerprint.
--delete-secret-and-public-key name
Same as --delete-key, but if a secret key exists, it
will be removed first. In batch mode the key must be
specified by fingerprint.
--export
Either export all keys from all keyrings (default keyr-
ings and those registered via option --keyring), or if
at least one name is given, those of the given name.
The new keyring is written to STDOUT or to the file
given with option --output. Use together with --armor
to mail those keys.
--send-keys key IDs
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Similar to --export but sends the keys to a keyserver.
Fingerprints may be used instead of key IDs. Option --
keyserver must be used to give the name of this
keyserver. Don't send your complete keyring to a
keyserver --- select only those keys which are new or
changed by you. If no key IDs are given, gpg does
nothing.
--export-secret-keys
--export-secret-subkeys
Same as --export, but exports the secret keys instead.
This is normally not very useful and a security risk.
The second form of the command has the special property
to render the secret part of the primary key useless;
this is a GNU extension to OpenPGP and other implemen-
tations can not be expected to successfully import such
a key. See the option --simple-sk-checksum if you want
to import such an exported key with an older OpenPGP
implementation.
--import
--fast-import
Import/merge keys. This adds the given keys to the
keyring. The fast version is currently just a synonym.
There are a few other options which control how this
command works. Most notable here is the --import-
options merge-only option which does not insert new
keys but does only the merging of new signatures,
user-IDs and subkeys.
--recv-keys key IDs
Import the keys with the given key IDs from a
keyserver. Option --keyserver must be used to give the
name of this keyserver.
--refresh-keys
Request updates from a keyserver for keys that already
exist on the local keyring. This is useful for updating
a key with the latest signatures, user IDs, etc. Cal-
ling this with no arguments will refresh the entire
keyring. Option --keyserver must be used to give the
name of the keyserver for all keys that do not have
preferred keyservers set (see --keyserver-options
honor-keyserver-url).
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--search-keys names
Search the keyserver for the given names. Multiple
names given here will be joined together to create the
search string for the keyserver. Option --keyserver
must be used to give the name of this keyserver.
Keyservers that support different search methods allow
using the syntax specified in "How to specify a user
ID" below. Note that different keyserver types support
different search methods. Currently only LDAP supports
them all.
--fetch-keys URIs
Retrieve keys located at the specified URIs. Note that
different installations of GnuPG may support different
protocols (HTTP, FTP, LDAP, etc.)
--update-trustdb
Do trust database maintenance. This command iterates
over all keys and builds the Web of Trust. This is an
interactive command because it may have to ask for the
"ownertrust" values for keys. The user has to give an
estimation of how far she trusts the owner of the
displayed key to correctly certify (sign) other keys.
GnuPG only asks for the ownertrust value if it has not
yet been assigned to a key. Using the --edit-key menu,
the assigned value can be changed at any time.
--check-trustdb
Do trust database maintenance without user interaction.
From time to time the trust database must be updated so
that expired keys or signatures and the resulting
changes in the Web of Trust can be tracked. Normally,
GnuPG will calculate when this is required and do it
automatically unless --no-auto-check-trustdb is set.
This command can be used to force a trust database
check at any time. The processing is identical to that
of --update-trustdb but it skips keys with a not yet
defined "ownertrust".
For use with cron jobs, this command can be used
together with --batch in which case the trust database
check is done only if a check is needed. To force a run
even in batch mode add the option --yes.
--export-ownertrust
Send the ownertrust values to STDOUT. This is useful
for backup purposes as these values are the only ones
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which can't be re-created from a corrupted trustdb.
Example:
gpg2 --export-ownertrust > otrust.txt
--import-ownertrust
Update the trustdb with the ownertrust values stored in
files (or STDIN if not given); existing values will be
overwritten. In case of a severely damaged trustdb and
if you have a recent backup of the ownertrust values
(e.g. in the file otrust.txt, you may re-create the
trustdb using these commands:
cd ~/.gnupg
rm trustdb.gpg
gpg2 --import-ownertrust < otrust.txt
--rebuild-keydb-caches
When updating from version 1.0.6 to 1.0.7 this command
should be used to create signature caches in the keyr-
ing. It might be handy in other situations too.
--print-md algo
--print-mds
Print message digest of algorithm ALGO for all given
files or STDIN. With the second form (or a deprecated
"*" as algo) digests for all available algorithms are
printed.
--gen-random 0|1|2
Emit count random bytes of the given quality level. If
count is not given or zero, an endless sequence of ran-
dom bytes will be emitted. PLEASE, don't use this com-
mand unless you know what you are doing; it may remove
precious entropy from the system!
--gen-prime mode bits
Use the source, Luke :-). The output format is still
subject to change.
--enarmor
--dearmor
Pack or unpack an arbitrary input into/from an OpenPGP
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ASCII armor. This is a GnuPG extension to OpenPGP and
in general not very useful.
How to manage your keys
This section explains the main commands for key management
--gen-key
Generate a new key pair. This command is normally only
used interactively.
There is an experimental feature which allows you to
create keys in batch mode. See the file doc/DETAILS in
the source distribution on how to use this.
--gen-revoke name
Generate a revocation certificate for the complete key.
To revoke a subkey or a signature, use the --edit com-
mand.
--desig-revoke name
Generate a designated revocation certificate for a key.
This allows a user (with the permission of the key-
holder) to revoke someone else's key.
--edit-key
Present a menu which enables you to do most of the key
management related tasks. It expects the specification
of a key on the command line.
uid n
Toggle selection of user ID or photographic user
ID with index n. Use * to select all and 0 to
deselect all.
key n
Toggle selection of subkey with index n. Use * to
select all and 0 to deselect all.
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sign Make a signature on key of user name If the key is
not yet signed by the default user (or the users
given with -u), the program displays the informa-
tion of the key again, together with its finger-
print and asks whether it should be signed. This
question is repeated for all users specified with
-u.
lsign
Same as "sign" but the signature is marked as
non-exportable and will therefore never be used by
others. This may be used to make keys valid only
in the local environment.
nrsign
Same as "sign" but the signature is marked as
non-revocable and can therefore never be revoked.
tsign
Make a trust signature. This is a signature that
combines the notions of certification (like a reg-
ular signature), and trust (like the "trust" com-
mand). It is generally only useful in distinct
communities or groups.
Note that "l" (for local / non-exportable), "nr" (for
non-revocable, and "t" (for trust) may be freely mixed
and prefixed to "sign" to create a signature of any
type desired.
delsig
Delete a signature. Note that it is not possible
to retract a signature, once it has been send to
the public (i.e. to a keyserver). In that case
you better use revsig.
revsig
Revoke a signature. For every signature which has
been generated by one of the secret keys, GnuPG
asks whether a revocation certificate should be
generated.
check
Check the signatures on all selected user IDs.
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adduid
Create an additional user ID.
addphoto
Create a photographic user ID. This will prompt
for a JPEG file that will be embedded into the
user ID. Note that a very large JPEG will make for
a very large key. Also note that some programs
will display your JPEG unchanged (GnuPG), and some
programs will scale it to fit in a dialog box
(PGP).
showphoto
Display the selected photographic user ID.
deluid
Delete a user ID or photographic user ID. Note
that it is not possible to retract a user id, once
it has been send to the public (i.e. to a
keyserver). In that case you better use revuid.
revuid
Revoke a user ID or photographic user ID.
primary
Flag the current user id as the primary one,
removes the primary user id flag from all other
user ids and sets the timestamp of all affected
self-signatures one second ahead. Note that set-
ting a photo user ID as primary makes it primary
over other photo user IDs, and setting a regular
user ID as primary makes it primary over other
regular user IDs.
keyserver
Set a preferred keyserver for the specified user
ID(s). This allows other users to know where you
prefer they get your key from. See --keyserver-
options honor-keyserver-url for more on how this
works. Setting a value of "none" removes an
existing preferred keyserver.
notation
Set a name=value notation for the specified user
ID(s). See --cert-notation for more on how this
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works. Setting a value of "none" removes all nota-
tions, setting a notation prefixed with a minus
sign (-) removes that notation, and setting a
notation name (without the =value) prefixed with a
minus sign removes all notations with that name.
pref List preferences from the selected user ID. This
shows the actual preferences, without including
any implied preferences.
showpref
More verbose preferences listing for the selected
user ID. This shows the preferences in effect by
including the implied preferences of 3DES
(cipher), SHA-1 (digest), and Uncompressed
(compression) if they are not already included in
the preference list. In addition, the preferred
keyserver and signature notations (if any) are
shown.
setpref string
Set the list of user ID preferences to string for
all (or just the selected) user IDs. Calling set-
pref with no arguments sets the preference list to
the default (either built-in or set via --
default-preference-list), and calling setpref with
"none" as the argument sets an empty preference
list. Use gpg2 --version to get a list of avail-
able algorithms. Note that while you can change
the preferences on an attribute user ID (aka
"photo ID"), GnuPG does not select keys via attri-
bute user IDs so these preferences will not be
used by GnuPG.
When setting preferences, you should list the
algorithms in the order which you'd like to see
them used by someone else when encrypting a mes-
sage to your key. If you don't include 3DES, it
will be automatically added at the end. Note that
there are many factors that go into choosing an
algorithm (for example, your key may not be the
only recipient), and so the remote OpenPGP appli-
cation being used to send to you may or may not
follow your exact chosen order for a given mes-
sage. It will, however, only choose an algorithm
that is present on the preference list of every
recipient key. See also the INTEROPERABILITY WITH
OTHER OPENPGP PROGRAMS section below.
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addkey
Add a subkey to this key.
addcardkey
Generate a subkey on a card and add it to this
key.
keytocard
Transfer the selected secret subkey (or the pri-
mary key if no subkey has been selected) to a
smartcard. The secret key in the keyring will be
replaced by a stub if the key could be stored suc-
cessfully on the card and you use the save command
later. Only certain key types may be transferred
to the card. A sub menu allows you to select on
what card to store the key. Note that it is not
possible to get that key back from the card - if
the card gets broken your secret key will be lost
unless you have a backup somewhere.
bkuptocard file
Restore the given file to a card. This command may
be used to restore a backup key (as generated dur-
ing card initialization) to a new card. In almost
all cases this will be the encryption key. You
should use this command only with the correspond-
ing public key and make sure that the file given
as argument is indeed the backup to restore. You
should then select 2 to restore as encryption key.
You will first be asked to enter the passphrase of
the backup key and then for the Admin PIN of the
card.
delkey
Remove a subkey (secondart key). Note that it is
not possible to retract a subkey, once it has been
send to the public (i.e. to a keyserver). In that
case you better use revkey.
revkey
Revoke a subkey.
expire
Change the key or subkey expiration time. If a
subkey is selected, the expiration time of this
subkey will be changed. With no selection, the key
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expiration of the primary key is changed.
trust
Change the owner trust value for the key. This
updates the trust-db immediately and no save is
required.
disable
enable
Disable or enable an entire key. A disabled key
can not normally be used for encryption.
addrevoker
Add a designated revoker to the key. This takes
one optional argument: "sensitive". If a desig-
nated revoker is marked as sensitive, it will not
be exported by default (see export-options).
passwd
Change the passphrase of the secret key.
toggle
Toggle between public and secret key listing.
clean
Compact (by removing all signatures except the
selfsig) any user ID that is no longer usable
(e.g. revoked, or expired). Then, remove any sig-
natures that are not usable by the trust calcula-
tions. Specifically, this removes any signature
that does not validate, any signature that is
superseded by a later signature, revoked signa-
tures, and signatures issued by keys that are not
present on the keyring.
minimize
Make the key as small as possible. This removes
all signatures from each user ID except for the
most recent self-signature.
cross-certify
Add cross-certification signatures to signing sub-
keys that may not currently have them. Cross-
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certification signatures protect against a subtle
attack against signing subkeys. See --require-
cross-certification. All new keys generated have
this signature by default, so this option is only
useful to bring older keys up to date.
save Save all changes to the key rings and quit.
quit Quit the program without updating the key rings.
The listing shows you the key with its secondary keys
and all user ids. Selected keys or user ids are indi-
cated by an asterisk. The trust value is displayed with
the primary key: the first is the assigned owner trust
and the second is the calculated trust value. Letters
are used for the values:
- No ownertrust assigned / not yet calculated.
e Trust calculation has failed; probably due to an
expired key.
q Not enough information for calculation.
n Never trust this key.
m Marginally trusted.
f Fully trusted.
u Ultimately trusted.
--sign-key name
Signs a public key with your secret key. This is a
shortcut version of the subcommand "sign" from --edit.
--lsign-key name
Signs a public key with your secret key but marks it as
non-exportable. This is a shortcut version of the
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subcommand "lsign" from --edit-key.
OPTIONS
gpg2 comes features a bunch of options to control the exact
behaviour and to change the default configuration.
Long options can be put in an options file (default
"~/.gnupg/gpg.conf"). Short option names will not work - for
example, "armor" is a valid option for the options file,
while "a" is not. Do not write the 2 dashes, but simply the
name of the option and any required arguments. Lines with a
hash ('#') as the first non-white-space character are
ignored. Commands may be put in this file too, but that is
not generally useful as the command will execute automati-
cally with every execution of gpg.
Please remember that option parsing stops as soon as a non-
option is encountered, you can explicitly stop parsing by
using the special option --.
How to change the configuration
These options are used to change the configuration and are
usually found in the option file.
--default-key name
Use name as the default key to sign with. If this
option is not used, the default key is the first key
found in the secret keyring. Note that -u or --local-
user overrides this option.
--default-recipient name
Use name as default recipient if option --recipient is
not used and don't ask if this is a valid one. name
must be non-empty.
--default-recipient-self
Use the default key as default recipient if option --
recipient is not used and don't ask if this is a valid
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one. The default key is the first one from the secret
keyring or the one set with --default-key.
--no-default-recipient
Reset --default-recipient and --default-recipient-self.
-v, --verbose
Give more information during processing. If used twice,
the input data is listed in detail.
--no-verbose
Reset verbose level to 0.
-q, --quiet
Try to be as quiet as possible.
--batch
--no-batch
Use batch mode. Never ask, do not allow interactive
commands. --no-batch disables this option. Note that
even with a filename given on the command line, gpg
might still need to read from STDIN (in particular if
gpg figures that the input is a detached signature and
no data file has been specified). Thus if you do not
want to feed data via STDIN, you should connect STDIN
to /dev/null.
--no-tty
Make sure that the TTY (terminal) is never used for any
output. This option is needed in some cases because
GnuPG sometimes prints warnings to the TTY even if --
batch is used.
--yes
Assume "yes" on most questions.
--no Assume "no" on most questions.
--list-options parameters
This is a space or comma delimited string that gives
options used when listing keys and signatures (that is,
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--list-keys, --list-sigs, --list-public-keys, --list-
secret-keys, and the --edit-key functions). Options
can be prepended with a no- (after the two dashes) to
give the opposite meaning. The options are:
show-photos
Causes --list-keys, --list-sigs, --list-public-
keys, and --list-secret-keys to display any photo
IDs attached to the key. Defaults to no. See also
--photo-viewer.
show-policy-urls
Show policy URLs in the --list-sigs or --check-
sigs listings. Defaults to no.
show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature
notations in the --list-sigs or --check-sigs list-
ings. Defaults to no.
show-keyserver-urls
Show any preferred keyserver URL in the --list-
sigs or --check-sigs listings. Defaults to no.
show-uid-validity
Display the calculated validity of user IDs during
key listings. Defaults to no.
show-unusable-uids
Show revoked and expired user IDs in key listings.
Defaults to no.
show-unusable-subkeys
Show revoked and expired subkeys in key listings.
Defaults to no.
show-keyring
Display the keyring name at the head of key
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listings to show which keyring a given key resides
on. Defaults to no.
show-sig-expire
Show signature expiration dates (if any) during
--list-sigs or --check-sigs listings. Defaults to
no.
show-sig-subpackets
Include signature subpackets in the key listing.
This option can take an optional argument list of
the subpackets to list. If no argument is passed,
list all subpackets. Defaults to no. This option
is only meaningful when using --with-colons along
with --list-sigs or --check-sigs.
--verify-options parameters
This is a space or comma delimited string that gives
options used when verifying signatures. Options can be
prepended with a `no-' to give the opposite meaning.
The options are:
show-photos
Display any photo IDs present on the key that
issued the signature. Defaults to no. See also
--photo-viewer.
show-policy-urls
Show policy URLs in the signature being verified.
Defaults to no.
show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature
notations in the signature being verified.
Defaults to IETF standard.
show-keyserver-urls
Show any preferred keyserver URL in the signature
being verified. Defaults to no.
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show-uid-validity
Display the calculated validity of the user IDs on
the key that issued the signature. Defaults to no.
show-unusable-uids
Show revoked and expired user IDs during signature
verification. Defaults to no.
show-primary-uid-only
Show only the primary user ID during signature
verification. That is all the AKA lines as well
as photo Ids are not shown with the signature
verification status.
pka-lookups
Enable PKA lookups to verify sender addresses.
Note that PKA is based on DNS, and so enabling
this option may disclose information on when and
what signatures are verified or to whom data is
encrypted. This is similar to the "web bug"
described for the auto-key-retrieve feature.
pka-trust-increase
Raise the trust in a signature to full if the sig-
nature passes PKA validation. This option is only
meaningful if pka-lookups is set.
--enable-dsa2
--disable-dsa2
Enable hash truncation for all DSA keys even for old
DSA Keys up to 1024 bit. This is also the default with
--openpgp. Note that older versions of GnuPG also
required this flag to allow the generation of DSA
larger than 1024 bit.
--photo-viewer string
This is the command line that should be run to view a
photo ID. "%i" will be expanded to a filename contain-
ing the photo. "%I" does the same, except the file will
not be deleted once the viewer exits. Other flags are
"%k" for the key ID, "%K" for the long key ID, "%f" for
the key fingerprint, "%t" for the extension of the
image type (e.g. "jpg"), "%T" for the MIME type of the
image (e.g. "image/jpeg"), and "%%" for an actual per-
cent sign. If neither %i or %I are present, then the
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photo will be supplied to the viewer on standard input.
The default viewer is "xloadimage -fork -quiet -title
'KeyID 0x%k' STDIN". Note that if your image viewer
program is not secure, then executing it from GnuPG
does not make it secure.
--exec-path string
Sets a list of directories to search for photo viewers
and keyserver helpers. If not provided, keyserver
helpers use the compiled-in default directory, and
photo viewers use the $PATH environment variable.
Note, that on W32 system this value is ignored when
searching for keyserver helpers.
--keyring file
Add file to the current 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 GnuPG home directory
("~/.gnupg" if --homedir or $GNUPGHOME is not used).
Note that this adds a keyring to the current list. If
the intent is to use the specified keyring alone, use
--keyring along with --no-default-keyring.
--secret-keyring file
Same as --keyring but for the secret keyrings.
--primary-keyring file
Designate file as the primary public keyring. This
means that newly imported keys (via --import or
keyserver --recv-from) will go to this keyring.
--trustdb-name file
Use file instead of the default trustdb. 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 GnuPG home directory
(~/.gnupg if --homedir or $GNUPGHOME is not used).
--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 com-
mand line. It also overrides any home directory stated
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through the environment variable GNUPGHOME or (on W32
systems) by means of the Registry entry
HKCU\Software\GNU\GnuPG:HomeDir.
--display-charset name
Set the name of the native character set. This is used
to convert some informational strings like user IDs to
the proper UTF-8 encoding. Note that this has nothing
to do with the character set of data to be encrypted or
signed; GnuPG does not recode user-supplied data. If
this option is not used, the default character set is
determined from the current locale. A verbosity level
of 3 shows the chosen set. Valid values for name are:
iso-8859-1
This is the Latin 1 set.
iso-8859-2
The Latin 2 set.
iso-8859-15
This is currently an alias for the Latin 1 set.
koi8-r
The usual Russian set (rfc1489).
utf-8
Bypass all translations and assume that the OS
uses native UTF-8 encoding.
--utf8-strings
--no-utf8-strings
Assume that command line arguments are given as UTF8
strings. The default (--no-utf8-strings) is to assume
that arguments are encoded in the character set as
specified by --display-charset. These options affect
all following arguments. Both options may be used mul-
tiple times.
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--options file
Read options from file and do not try to read them from
the default options file in the homedir (see --
homedir). This option is ignored if used in an options
file.
--no-options
Shortcut for --options /dev/null. This option is
detected before an attempt to open an option file.
Using this option will also prevent the creation of a
~/.gnupg homedir.
-z n
--compress-level n
--bzip2-compress-level n
Set compression level to n for the ZIP and ZLIB
compression algorithms. The default is to use the
default compression level of zlib (normally 6). --
bzip2-compress-level sets the compression level for the
BZIP2 compression algorithm (defaulting to 6 as well).
This is a different option from --compress-level since
BZIP2 uses a significant amount of memory for each
additional compression level. -z sets both. A value of
0 for n disables compression.
--bzip2-decompress-lowmem
Use a different decompression method for BZIP2
compressed files. This alternate method uses a bit more
than half the memory, but also runs at half the speed.
This is useful under extreme low memory circumstances
when the file was originally compressed at a high --
bzip2-compress-level.
--mangle-dos-filenames
--no-mangle-dos-filenames
Older version of Windows cannot handle filenames with
more than one dot. --mangle-dos-filenames causes GnuPG
to replace (rather than add to) the extension of an
output filename to avoid this problem. This option is
off by default and has no effect on non-Windows plat-
forms.
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--ask-cert-level
--no-ask-cert-level
When making a key signature, prompt for a certification
level. If this option is not specified, the certifica-
tion level used is set via --default-cert-level. See
--default-cert-level for information on the specific
levels and how they are used. --no-ask-cert-level dis-
ables this option. This option defaults to no.
--default-cert-level n
The default to use for the check level when signing a
key.
0 means you make no particular claim as to how care-
fully you verified the key.
1 means you believe the key is owned by the person who
claims to own it but you could not, or did not verify
the key at all. This is useful for a "persona" verifi-
cation, where you sign the key of a pseudonymous user.
2 means you did casual verification of the key. For
example, this could mean that you verified that the key
fingerprint and checked the user ID on the key against
a photo ID.
3 means you did extensive verification of the key. For
example, this could mean that you verified the key
fingerprint with the owner of the key in person, and
that you checked, by means of a hard to forge document
with a photo ID (such as a passport) that the name of
the key owner matches the name in the user ID on the
key, and finally that you verified (by exchange of
email) that the email address on the key belongs to the
key owner.
Note that the examples given above for levels 2 and 3
are just that: examples. In the end, it is up to you
to decide just what "casual" and "extensive" mean to
you.
This option defaults to 0 (no particular claim).
--min-cert-level
When building the trust database, treat any signatures
with a certification level below this as invalid.
Defaults to 2, which disregards level 1 signatures.
Note that level 0 "no particular claim" signatures are
always accepted.
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--trusted-key long key ID
Assume that the specified key (which must be given as a
full 8 byte key ID) is as trustworthy as one of your
own secret keys. This option is useful if you don't
want to keep your secret keys (or one of them) online
but still want to be able to check the validity of a
given recipient's or signator's key.
--trust-model pgp|classic|direct|always|auto
Set what trust model GnuPG should follow. The models
are:
pgp This is the Web of Trust combined with trust sig-
natures as used in PGP 5.x and later. This is the
default trust model when creating a new trust
database.
classic
This is the standard Web of Trust as used in PGP
2.x and earlier.
direct
Key validity is set directly by the user and not
calculated via the Web of Trust.
always
Skip key validation and assume that used keys are
always fully trusted. You generally won't use this
unless you are using some external validation
scheme. This option also suppresses the "[uncer-
tain]" tag printed with signature checks when
there is no evidence that the user ID is bound to
the key.
auto Select the trust model depending on whatever the
internal trust database says. This is the default
model if such a database already exists.
--auto-key-locate parameters
--no-auto-key-locate
GnuPG can automatically locate and retrieve keys as
needed using this option. This happens when encrypting
to an email address (in the "user@example.com" form),
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and there are no user@example.com keys on the local
keyring. This option takes any number of the following
mechanisms, in the order they are to be tried:
cert Locate a key using DNS CERT, as specified in
rfc4398.
pka Locate a key using DNS PKA.
ldap Using DNS Service Discovery, check the domain in
question for any LDAP keyservers to use. If this
fails, attempt to locate the key using the PGP
Universal method of checking
ldap://keys.(thedomain).
keyserver
Locate a key using whatever keyserver is defined
using the --keyserver option.
keyserver-URL
In addition, a keyserver URL as used in the --
keyserver option may be used here to query that
particular keyserver.
local
Locate the key using the local keyrings. This
mechanism allows to select the order a local key
lookup is done. Thus using --auto-key-locate
local is identical to --no-auto-key-locate.
nodefault
This flag disables the standard local key lookup,
done before any of the mechanisms defined by the
--auto-key-locate are tried. The position of this
mechanism in the list does not matter. It is not
required if local is also used.
--keyid-format short|0xshort|long|0xlong
Select how to display key IDs. "short" is the tradi-
tional 8-character key ID. "long" is the more accurate
(but less convenient) 16-character key ID. Add an "0x"
to either to include an "0x" at the beginning of the
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key ID, as in 0x99242560.
--keyserver name
Use name as your keyserver. This is the server that --
recv-keys, --send-keys, and --search-keys will communi-
cate with to receive keys from, send keys to, and
search for keys on. The format of the name is a URI:
`scheme:[//]keyservername[:port]' The scheme is the
type of keyserver: "hkp" for the HTTP (or compatible)
keyservers, "ldap" for the LDAP keyservers, or "mailto"
for the Graff email keyserver. Note that your particu-
lar installation of GnuPG may have other keyserver
types available as well. Keyserver schemes are case-
insensitive. After the keyserver name, optional
keyserver configuration options may be provided. These
are the same as the global --keyserver-options from
below, but apply only to this particular keyserver.
Most keyservers synchronize with each other, so there
is generally no need to send keys to more than one
server. The keyserver hkp://keys.gnupg.net uses round
robin DNS to give a different keyserver each time you
use it.
--keyserver-options name=value1
This is a space or comma delimited string that gives
options for the keyserver. Options can be prefixed with
a `no-' to give the opposite meaning. Valid import-
options or export-options may be used here as well to
apply to importing (--recv-key) or exporting (--send-
key) a key from a keyserver. While not all options are
available for all keyserver types, some common options
are:
include-revoked
When searching for a key with --search-keys,
include keys that are marked on the keyserver as
revoked. Note that not all keyservers differen-
tiate between revoked and unrevoked keys, and for
such keyservers this option is meaningless. Note
also that most keyservers do not have crypto-
graphic verification of key revocations, and so
turning this option off may result in skipping
keys that are incorrectly marked as revoked.
include-disabled
When searching for a key with --search-keys,
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include keys that are marked on the keyserver as
disabled. Note that this option is not used with
HKP keyservers.
auto-key-retrieve
This option enables the automatic retrieving of
keys from a keyserver when verifying signatures
made by keys that are not on the local keyring.
Note that this option makes a "web bug" like
behavior possible. Keyserver operators can see
which keys you request, so by sending you a mes-
sage signed by a brand new key (which you natur-
ally will not have on your local keyring), the
operator can tell both your IP address and the
time when you verified the signature.
honor-keyserver-url
When using --refresh-keys, if the key in question
has a preferred keyserver URL, then use that pre-
ferred keyserver to refresh the key from. In addi-
tion, if auto-key-retrieve is set, and the signa-
ture being verified has a preferred keyserver URL,
then use that preferred keyserver to fetch the key
from. Defaults to yes.
honor-pka-record
If auto-key-retrieve is set, and the signature
being verified has a PKA record, then use the PKA
information to fetch the key. Defaults to yes.
include-subkeys
When receiving a key, include subkeys as potential
targets. Note that this option is not used with
HKP keyservers, as they do not support retrieving
keys by subkey id.
use-temp-files
On most Unix-like platforms, GnuPG communicates
with the keyserver helper program via pipes, which
is the most efficient method. This option forces
GnuPG to use temporary files to communicate. On
some platforms (such as Win32 and RISC OS), this
option is always enabled.
keep-temp-files
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If using `use-temp-files', do not delete the temp
files after using them. This option is useful to
learn the keyserver communication protocol by
reading the temporary files.
verbose
Tell the keyserver helper program to be more ver-
bose. This option can be repeated multiple times
to increase the verbosity level.
timeout
Tell the keyserver helper program how long (in
seconds) to try and perform a keyserver action
before giving up. Note that performing multiple
actions at the same time uses this timeout value
per action. For example, when retrieving multiple
keys via --recv-keys, the timeout applies
separately to each key retrieval, and not to the
--recv-keys command as a whole. Defaults to 30
seconds.
http-proxy=value
Set the proxy to use for HTTP and HKP keyservers.
This overrides the "http_proxy" environment vari-
able, if any.
max-cert-size
When retrieving a key via DNS CERT, only accept
keys up to this size. Defaults to 16384 bytes.
debug
Turn on debug output in the keyserver helper pro-
gram. Note that the details of debug output
depends on which keyserver helper program is being
used, and in turn, on any libraries that the
keyserver helper program uses internally (libcurl,
openldap, etc).
check-cert
Enable certificate checking if the keyserver
presents one (for hkps or ldaps). Defaults to on.
ca-cert-file
Provide a certificate file to override the system
default. Only necessary if check-cert is enabled,
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and the keyserver is using a certificate that is
not present in a system default certificate list.
--completes-needed n
Number of completely trusted users to introduce a new
key signer (defaults to 1).
--marginals-needed n
Number of marginally trusted users to introduce a new
key signer (defaults to 3)
--max-cert-depth n
Maximum depth of a certification chain (default is 5).
--simple-sk-checksum
Secret keys are integrity protected by using a SHA-1
checksum. This method is part of the upcoming enhanced
OpenPGP specification but GnuPG already uses it as a
countermeasure against certain attacks. Old applica-
tions don't understand this new format, so this option
may be used to switch back to the old behaviour. Using
this option bears a security risk. Note that using this
option only takes effect when the secret key is
encrypted - the simplest way to make this happen is to
change the passphrase on the key (even changing it to
the same value is acceptable).
--no-sig-cache
Do not cache the verification status of key signatures.
Caching gives a much better performance in key list-
ings. However, if you suspect that your public keyring
is not save against write modifications, you can use
this option to disable the caching. It probably does
not make sense to disable it because all kind of damage
can be done if someone else has write access to your
public keyring.
--no-sig-create-check
GnuPG normally verifies each signature right after
creation to protect against bugs and hardware malfunc-
tions which could leak out bits from the secret key.
This extra verification needs some time (about 115% for
DSA keys), and so this option can be used to disable
it. However, due to the fact that the signature crea-
tion needs manual interaction, this performance penalty
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does not matter in most settings.
--auto-check-trustdb
--no-auto-check-trustdb
If GnuPG feels that its information about the Web of
Trust has to be updated, it automatically runs the --
check-trustdb command internally. This may be a time
consuming process. --no-auto-check-trustdb disables
this option.
--use-agent
--no-use-agent
This is dummy option. gpg2 always requires the agent.
--gpg-agent-info
This is dummy option. It has no effect when used with
gpg2.
--lock-once
Lock the databases the first time a lock is requested
and do not release the lock until the process ter-
minates.
--lock-multiple
Release the locks every time a lock is no longer
needed. Use this to override a previous --lock-once
from a config file.
--lock-never
Disable locking entirely. This option should be used
only in very special environments, where it can be
assured that only one process is accessing those files.
A bootable floppy with a stand-alone encryption system
will probably use this. Improper usage of this option
may lead to data and key corruption.
--exit-on-status-write-error
This option will cause write errors on the status FD to
immediately terminate the process. That should in fact
be the default but it never worked this way and thus we
need an option to enable this, so that the change won't
break applications which close their end of a status fd
connected pipe too early. Using this option along with
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--enable-progress-filter may be used to cleanly cancel
long running gpg operations.
--limit-card-insert-tries n
With n greater than 0 the number of prompts asking to
insert a smartcard gets limited to N-1. Thus with a
value of 1 gpg won't at all ask to insert a card if
none has been inserted at startup. This option is use-
ful in the configuration file in case an application
does not know about the smartcard support and waits ad
infinitum for an inserted card.
--no-random-seed-file
GnuPG uses a file to store its internal random pool
over invocations. This makes random generation faster;
however sometimes write operations are not desired.
This option can be used to achieve that with the cost
of slower random generation.
--no-greeting
Suppress the initial copyright message.
--no-secmem-warning
Suppress the warning about "using insecure memory".
--no-permission-warning
Suppress the warning about unsafe file and home direc-
tory (--homedir) permissions. Note that the permission
checks that GnuPG performs are not intended to be
authoritative, but rather they simply warn about cer-
tain common permission problems. Do not assume that the
lack of a warning means that your system is secure.
Note that the warning for unsafe --homedir permissions
cannot be suppressed in the gpg.conf file, as this
would allow an attacker to place an unsafe gpg.conf
file in place, and use this file to suppress warnings
about itself. The --homedir permissions warning may
only be suppressed on the command line.
--no-mdc-warning
Suppress the warning about missing MDC integrity pro-
tection.
--require-secmem
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--no-require-secmem
Refuse to run if GnuPG cannot get secure memory.
Defaults to no (i.e. run, but give a warning).
--require-cross-certification
--no-require-cross-certification
When verifying a signature made from a subkey, ensure
that the cross certification "back signature" on the
subkey is present and valid. This protects against a
subtle attack against subkeys that can sign. Defaults
to --require-cross-certification for gpg2.
--expert
--no-expert
Allow the user to do certain nonsensical or "silly"
things like signing an expired or revoked key, or cer-
tain potentially incompatible things like generating
unusual key types. This also disables certain warning
messages about potentially incompatible actions. As the
name implies, this option is for experts only. If you
don't fully understand the implications of what it
allows you to do, leave this off. --no-expert disables
this option.
Key related options
--recipient name
-r Encrypt for user id name. If this option or --hidden-
recipient is not specified, GnuPG asks for the user-id
unless --default-recipient is given.
--hidden-recipient name
-R Encrypt for user ID name, but hide the key ID of this
user's key. This option helps to hide the receiver of
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the message and is a limited countermeasure against
traffic analysis. If this option or --recipient is not
specified, GnuPG asks for the user ID unless --
default-recipient is given.
--encrypt-to name
Same as --recipient but this one is intended for use in
the options file and may be used with your own user-id
as an "encrypt-to-self". These keys are only used when
there are other recipients given either by use of --
recipient or by the asked user id. No trust checking
is performed for these user ids and even disabled keys
can be used.
--hidden-encrypt-to name
Same as --hidden-recipient but this one is intended for
use in the options file and may be used with your own
user-id as a hidden "encrypt-to-self". These keys are
only used when there are other recipients given either
by use of --recipient or by the asked user id. No
trust checking is performed for these user ids and even
disabled keys can be used.
--no-encrypt-to
Disable the use of all --encrypt-to and --hidden-
encrypt-to keys.
--group name=value1
Sets up a named group, which is similar to aliases in
email programs. Any time the group name is a recipient
(-r or --recipient), it will be expanded to the values
specified. Multiple groups with the same name are
automatically merged into a single group.
The values are key IDs or fingerprints, but any key
description is accepted. Note that a value with spaces
in it will be treated as two different values. Note
also there is only one level of expansion --- you can-
not make an group that points to another group. When
used from the command line, it may be necessary to
quote the argument to this option to prevent the shell
from treating it as multiple arguments.
--ungroup name
Remove a given entry from the --group list.
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--no-groups
Remove all entries from the --group list.
--local-user name
-u Use name as the key to sign with. Note that this option
overrides --default-key.
--try-all-secrets
Don't look at the key ID as stored in the message but
try all secret keys in turn to find the right decryp-
tion key. This option forces the behaviour as used by
anonymous recipients (created by using --throw-keyids)
and might come handy in case where an encrypted message
contains a bogus key ID.
Input and Output
--armor
-a Create ASCII armored output. The default is to create
the binary OpenPGP format.
--no-armor
Assume the input data is not in ASCII armored format.
--output file
-o file
Write output to file.
--max-output n
This option sets a limit on the number of bytes that
will be generated when processing a file. Since OpenPGP
supports various levels of compression, it is possible
that the plaintext of a given message may be signifi-
cantly larger than the original OpenPGP message. While
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GNU Privacy Guard GPG2(1)
GnuPG works properly with such messages, there is often
a desire to set a maximum file size that will be gen-
erated before processing is forced to stop by the OS
limits. Defaults to 0, which means "no limit".
--import-options parameters
This is a space or comma delimited string that gives
options for importing keys. Options can be prepended
with a `no-' to give the opposite meaning. The options
are:
import-local-sigs
Allow importing key signatures marked as "local".
This is not generally useful unless a shared keyr-
ing scheme is being used. Defaults to no.
repair-pks-subkey-bug
During import, attempt to repair the damage caused
by the PKS keyserver bug (pre version 0.9.6) that
mangles keys with multiple subkeys. Note that this
cannot completely repair the damaged key as some
crucial data is removed by the keyserver, but it
does at least give you back one subkey. Defaults
to no for regular --import and to yes for
keyserver --recv-keys.
merge-only
During import, allow key updates to existing keys,
but do not allow any new keys to be imported.
Defaults to no.
import-clean
After import, compact (remove all signatures
except the self-signature) any user IDs from the
new key that are not usable. Then, remove any
signatures from the new key that are not usable.
This includes signatures that were issued by keys
that are not present on the keyring. This option
is the same as running the --edit-key command
"clean" after import. Defaults to no.
import-minimal
Import the smallest key possible. This removes all
signatures except the most recent self-signature
on each user ID. This option is the same as
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GNU Privacy Guard GPG2(1)
running the --edit-key command "minimize" after
import. Defaults to no.
--export-options parameters
This is a space or comma delimited string that gives
options for exporting keys. Options can be prepended
with a `no-' to give the opposite meaning. The options
are:
export-local-sigs
Allow exporting key signatures marked as "local".
This is not generally useful unless a shared keyr-
ing scheme is being used. Defaults to no.
export-attributes
Include attribute user IDs (photo IDs) while
exporting. This is useful to export keys if they
are going to be used by an OpenPGP program that
does not accept attribute user IDs. Defaults to
yes.
export-sensitive-revkeys
Include designated revoker information that was
marked as "sensitive". Defaults to no.
export-reset-subkey-passwd
When using the --export-secret-subkeys command,
this option resets the passphrases for all
exported subkeys to empty. This is useful when the
exported subkey is to be used on an unattended
machine where a passphrase doesn't necessarily
make sense. Defaults to no.
export-clean
Compact (remove all signatures from) user IDs on
the key being exported if the user IDs are not
usable. Also, do not export any signatures that
are not usable. This includes signatures that were
issued by keys that are not present on the keyr-
ing. This option is the same as running the --
edit-key command "clean" before export except that
the local copy of the key is not modified.
Defaults to no.
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export-minimal
Export the smallest key possible. This removes all
signatures except the most recent self-signature
on each user ID. This option is the same as run-
ning the --edit-key command "minimize" before
export except that the local copy of the key is
not modified. Defaults to no.
--with-colons
Print key listings delimited by colons. Note that the
output will be encoded in UTF-8 regardless of any --
display-charset setting. This format is useful when
GnuPG is called from scripts and other programs as it
is easily machine parsed. The details of this format
are documented in the file doc/DETAILS, which is
included in the GnuPG source distribution.
--fixed-list-mode
Do not merge primary user ID and primary key in --
with-colon listing mode and print all timestamps as
seconds since 1970-01-01. Since GnuPG 2.0.10, this
mode is always used and thus this option is obsolete;
it does not harm to use it though.
--with-fingerprint
Same as the command --fingerprint but changes only the
format of the output and may be used together with
another command.
OpenPGP protocol specific options.
-t, --textmode
--no-textmode
Treat input files as text and store them in the OpenPGP
canonical text form with standard "CRLF" line endings.
This also sets the necessary flags to inform the reci-
pient that the encrypted or signed data is text and may
need its line endings converted back to whatever the
local system uses. This option is useful when communi-
cating between two platforms that have different line
ending conventions (UNIX-like to Mac, Mac to Windows,
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GNU Privacy Guard GPG2(1)
etc). --no-textmode disables this option, and is the
default.
--force-v3-sigs
--no-force-v3-sigs
OpenPGP states that an implementation should generate
v4 signatures but PGP versions 5 through 7 only recog-
nize v4 signatures on key material. This option forces
v3 signatures for signatures on data. Note that this
option implies --ask-sig-expire, --sig-policy-url, --
sig-notation, and --sig-keyserver-url, as these
features cannot be used with v3 signatures. --no-
force-v3-sigs disables this option.
--force-v4-certs
--no-force-v4-certs
Always use v4 key signatures even on v3 keys. This
option also changes the default hash algorithm for v3
RSA keys from MD5 to SHA-1. --no-force-v4-certs dis-
ables this option.
--force-mdc
Force the use of encryption with a modification detec-
tion code. This is always used with the newer ciphers
(those with a blocksize greater than 64 bits), or if
all of the recipient keys indicate MDC support in their
feature flags.
--disable-mdc
Disable the use of the modification detection code.
Note that by using this option, the encrypted message
becomes vulnerable to a message modification attack.
--personal-cipher-preferences string
Set the list of personal cipher preferences to string.
Use gpg2 --version to get a list of available algo-
rithms, and use none to set no preference at all. This
allows the user to safely override the algorithm chosen
by the recipient key preferences, as GPG will only
select an algorithm that is usable by all recipients.
The most highly ranked cipher in this list is also used
for the --symmetric encryption command.
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--personal-digest-preferences string
Set the list of personal digest preferences to string.
Use gpg2 --version to get a list of available algo-
rithms, and use none to set no preference at all. This
allows the user to safely override the algorithm chosen
by the recipient key preferences, as GPG will only
select an algorithm that is usable by all recipients.
The most highly ranked digest algorithm in this list is
also used when signing without encryption (e.g. --
clearsign or --sign). The default value is SHA-1.
--personal-compress-preferences string
Set the list of personal compression preferences to
string. Use gpg2 --version to get a list of available
algorithms, and use none to set no preference at all.
This allows the user to safely override the algorithm
chosen by the recipient key preferences, as GPG will
only select an algorithm that is usable by all reci-
pients. The most highly ranked compression algorithm
in this list is also used when there are no recipient
keys to consider (e.g. --symmetric).
--s2k-cipher-algo name
Use name as the cipher algorithm used to protect secret
keys. The default cipher is CAST5. This cipher is also
used for conventional encryption if --personal-cipher-
preferences and --cipher-algo is not given.
--s2k-digest-algo name
Use name as the digest algorithm used to mangle the
passphrases. The default algorithm is SHA-1.
--s2k-mode n
Selects how passphrases are mangled. If n is 0 a plain
passphrase (which is not recommended) will be used, a 1
adds a salt to the passphrase and a 3 (the default)
iterates the whole process a number of times (see --
s2k-count). Unless --rfc1991 is used, this mode is
also used for conventional encryption.
--s2k-count n
Specify how many times the passphrase mangling is
repeated. This value may range between 1024 and
65011712 inclusive, and the default is 65536. Note
that not all values in the 1024-65011712 range are
legal and if an illegal value is selected, GnuPG will
round up to the nearest legal value. This option is
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only meaningful if --s2k-mode is 3.
Compliance options
These options control what GnuPG is compliant to. Only one
of these options may be active at a time. Note that the
default setting of this is nearly always the correct one.
See the INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS section
below before using one of these options.
--gnupg
Use standard GnuPG behavior. This is essentially
OpenPGP behavior (see --openpgp), but with some addi-
tional workarounds for common compatibility problems in
different versions of PGP. This is the default option,
so it is not generally needed, but it may be useful to
override a different compliance option in the gpg.conf
file.
--openpgp
Reset all packet, cipher and digest options to strict
OpenPGP behavior. Use this option to reset all previous
options like --s2k-*, --cipher-algo, --digest-algo and
--compress-algo to OpenPGP compliant values. All PGP
workarounds are disabled.
--rfc4880
Reset all packet, cipher and digest options to strict
RFC-4880 behavior. Note that this is currently the same
thing as --openpgp.
--rfc2440
Reset all packet, cipher and digest options to strict
RFC-2440 behavior.
--rfc1991
Try to be more RFC-1991 (PGP 2.x) compliant.
--pgp2
Set up all options to be as PGP 2.x compliant as
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possible, and warn if an action is taken (e.g. encrypt-
ing to a non-RSA key) that will create a message that
PGP 2.x will not be able to handle. Note that `PGP 2.x'
here means `MIT PGP 2.6.2'. There are other versions of
PGP 2.x available, but the MIT release is a good common
baseline.
This option implies --rfc1991 --disable-mdc --no-
force-v4-certs --escape-from-lines --force-v3-sigs --
cipher-algo IDEA --digest-algo MD5 --compress-algo ZIP.
It also disables --textmode when encrypting.
--pgp6
Set up all options to be as PGP 6 compliant as possi-
ble. This restricts you to the ciphers IDEA (if the
IDEA plugin is installed), 3DES, and CAST5, the hashes
MD5, SHA1 and RIPEMD160, and the compression algorithms
none and ZIP. This also disables --throw-keyids, and
making signatures with signing subkeys as PGP 6 does
not understand signatures made by signing subkeys.
This option implies --disable-mdc --escape-from-lines
--force-v3-sigs.
--pgp7
Set up all options to be as PGP 7 compliant as possi-
ble. This is identical to --pgp6 except that MDCs are
not disabled, and the list of allowable ciphers is
expanded to add AES128, AES192, AES256, and TWOFISH.
--pgp8
Set up all options to be as PGP 8 compliant as possi-
ble. PGP 8 is a lot closer to the OpenPGP standard than
previous versions of PGP, so all this does is disable
--throw-keyids and set --escape-from-lines. All algo-
rithms are allowed except for the SHA224, SHA384, and
SHA512 digests.
Doing things one usually doesn't want
-n
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--dry-run
Don't make any changes (this is not completely imple-
mented).
--list-only
Changes the behaviour of some commands. This is like
--dry-run but different in some cases. The semantic of
this command may be extended in the future. Currently
it only skips the actual decryption pass and therefore
enables a fast listing of the encryption keys.
-i
--interactive
Prompt before overwriting any files.
--debug flags
Set debugging flags. All flags are or-ed and flags may
be given in C syntax (e.g. 0x0042).
--debug-all
Set all useful debugging flags.
--enable-progress-filter
Enable certain PROGRESS status outputs. This option
allows frontends to display a progress indicator while
gpg is processing larger files. There is a slight per-
formance overhead using it.
--status-fd n
Write special status strings to the file descriptor n.
See the file DETAILS in the documentation for a listing
of them.
--status-file file
Same as --status-fd, except the status data is written
to file file.
--logger-fd n
Write log output to file descriptor n and not to
STDERR.
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--log-file file
--logger-file file
Same as --logger-fd, except the logger data is written
to file file. Note that --log-file is only implemented
for GnuPG-2.
--attribute-fd n
Write attribute subpackets to the file descriptor n.
This is most useful for use with --status-fd, since the
status messages are needed to separate out the various
subpackets from the stream delivered to the file
descriptor.
--attribute-file file
Same as --attribute-fd, except the attribute data is
written to file file.
--comment string
--no-comments
Use string as a comment string in clear text signatures
and ASCII armored messages or keys (see --armor). The
default behavior is not to use a comment string. --
comment may be repeated multiple times to get multiple
comment strings. --no-comments removes all comments.
It is a good idea to keep the length of a single com-
ment below 60 characters to avoid problems with mail
programs wrapping such lines. Note that comment lines,
like all other header lines, are not protected by the
signature.
--emit-version
--no-emit-version
Force inclusion of the version string in ASCII armored
output. --no-emit-version disables this option.
--sig-notation name=value
--cert-notation name=value
-N, --set-notation name=value
Put the name value pair into the signature as notation
data. name must consist only of printable characters
or spaces, and must contain a '@' character in the form
keyname@domain.example.com (substituting the
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GNU Privacy Guard GPG2(1)
appropriate keyname and domain name, of course). This
is to help prevent pollution of the IETF reserved nota-
tion namespace. The --expert flag overrides the '@'
check. value may be any printable string; it will be
encoded in UTF8, so you should check that your --
display-charset is set correctly. If you prefix name
with an exclamation mark (!), the notation data will be
flagged as critical (rfc2440:5.2.3.15). --sig-notation
sets a notation for data signatures. --cert-notation
sets a notation for key signatures (certifications).
--set-notation sets both.
There are special codes that may be used in notation
names. "%k" will be expanded into the key ID of the key
being signed, "%K" into the long key ID of the key
being signed, "%f" into the fingerprint of the key
being signed, "%s" into the key ID of the key making
the signature, "%S" into the long key ID of the key
making the signature, "%g" into the fingerprint of the
key making the signature (which might be a subkey),
"%p" into the fingerprint of the primary key of the key
making the signature, "%c" into the signature count
from the OpenPGP smartcard, and "%%" results in a sin-
gle "%". %k, %K, and %f are only meaningful when making
a key signature (certification), and %c is only mean-
ingful when using the OpenPGP smartcard.
--sig-policy-url string
--cert-policy-url string
--set-policy-url string
Use string as a Policy URL for signatures
(rfc2440:5.2.3.19). If you prefix it with an exclama-
tion mark (!), the policy URL packet will be flagged as
critical. --sig-policy-url sets a policy url for data
signatures. --cert-policy-url sets a policy url for key
signatures (certifications). --set-policy-url sets
both.
The same %-expandos used for notation data are avail-
able here as well.
--sig-keyserver-url string
Use string as a preferred keyserver URL for data signa-
tures. If you prefix it with an exclamation mark (!),
the keyserver URL packet will be flagged as critical.
The same %-expandos used for notation data are avail-
able here as well.
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GNU Privacy Guard GPG2(1)
--set-filename string
Use string as the filename which is stored inside mes-
sages. This overrides the default, which is to use the
actual filename of the file being encrypted.
--for-your-eyes-only
--no-for-your-eyes-only
Set the `for your eyes only' flag in the message. This
causes GnuPG to refuse to save the file unless the --
output option is given, and PGP to use a "secure
viewer" with a claimed Tempest-resistant font to
display the message. This option overrides --set-
filename. --no-for-your-eyes-only disables this
option.
--use-embedded-filename
--no-use-embedded-filename
Try to create a file with a name as embedded in the
data. This can be a dangerous option as it allows to
overwrite files. Defaults to no.
--cipher-algo name
Use name as cipher algorithm. Running the program with
the command --version yields a list of supported algo-
rithms. If this is not used the cipher algorithm is
selected from the preferences stored with the key. In
general, you do not want to use this option as it
allows you to violate the OpenPGP standard. --
personal-cipher-preferences is the safe way to accom-
plish the same thing.
--digest-algo name
Use name as the message digest algorithm. Running the
program with the command --version yields a list of
supported algorithms. In general, you do not want to
use this option as it allows you to violate the OpenPGP
standard. --personal-digest-preferences is the safe way
to accomplish the same thing.
--compress-algo name
Use compression algorithm name. "zlib" is RFC-1950 ZLIB
compression. "zip" is RFC-1951 ZIP compression which is
used by PGP. "bzip2" is a more modern compression
scheme that can compress some things better than zip or
zlib, but at the cost of more memory used during
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GNU Privacy Guard GPG2(1)
compression and decompression. "uncompressed" or "none"
disables compression. If this option is not used, the
default behavior is to examine the recipient key
preferences to see which algorithms the recipient sup-
ports. If all else fails, ZIP is used for maximum com-
patibility.
ZLIB may give better compression results than ZIP, as
the compression window size is not limited to 8k. BZIP2
may give even better compression results than that, but
will use a significantly larger amount of memory while
compressing and decompressing. This may be significant
in low memory situations. Note, however, that PGP (all
versions) only supports ZIP compression. Using any
algorithm other than ZIP or "none" will make the mes-
sage unreadable with PGP. In general, you do not want
to use this option as it allows you to violate the
OpenPGP standard. --personal-compress-preferences is
the safe way to accomplish the same thing.
--cert-digest-algo name
Use name as the message digest algorithm used when
signing a key. Running the program with the command --
version yields a list of supported algorithms. Be aware
that if you choose an algorithm that GnuPG supports but
other OpenPGP implementations do not, then some users
will not be able to use the key signatures you make, or
quite possibly your entire key.
--disable-cipher-algo name
Never allow the use of name as cipher algorithm. The
given name will not be checked so that a later loaded
algorithm will still get disabled.
--disable-pubkey-algo name
Never allow the use of name as public key algorithm.
The given name will not be checked so that a later
loaded algorithm will still get disabled.
--throw-keyids
--no-throw-keyids
Do not put the recipient key IDs into encrypted mes-
sages. This helps to hide the receivers of the message
and is a limited countermeasure against traffic
analysis. ([Using a little social engineering anyone
who is able to decrypt the message can check whether
one of the other recipients is the one he suspects.])
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On the receiving side, it may slow down the decryption
process because all available secret keys must be
tried. --no-throw-keyids disables this option. This
option is essentially the same as using --hidden-
recipient for all recipients.
--not-dash-escaped
This option changes the behavior of cleartext signa-
tures so that they can be used for patch files. You
should not send such an armored file via email because
all spaces and line endings are hashed too. You can not
use this option for data which has 5 dashes at the
beginning of a line, patch files don't have this. A
special armor header line tells GnuPG about this clear-
text signature option.
--escape-from-lines
--no-escape-from-lines
Because some mailers change lines starting with "From "
to ">From " it is good to handle such lines in a spe-
cial way when creating cleartext signatures to prevent
the mail system from breaking the signature. Note that
all other PGP versions do it this way too. Enabled by
default. --no-escape-from-lines disables this option.
--passphrase-repeat n
Specify how many times gpg2 will request a new
passphrase be repeated. This is useful for helping
memorize a passphrase. Defaults to 1 repetition.
--passphrase-fd n
Read the passphrase from file descriptor n. Only the
first line will be read from file descriptor n. If you
use 0 for n, the passphrase will be read from STDIN.
This can only be used if only one passphrase is sup-
plied. Note that this passphrase is only used if the
option --batch has also been given. This is different
from gpg.
--passphrase-file file
Read the passphrase from file file. Only the first line
will be read from file file. This can only be used if
only one passphrase is supplied. Obviously, a
passphrase stored in a file is of questionable security
if other users can read this file. Don't use this
option if you can avoid it. Note that this passphrase
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GNU Privacy Guard GPG2(1)
is only used if the option --batch has also been given.
This is different from gpg.
--passphrase string
Use string as the passphrase. This can only be used if
only one passphrase is supplied. Obviously, this is of
very questionable security on a multi-user system.
Don't use this option if you can avoid it. Note that
this passphrase is only used if the option --batch has
also been given. This is different from gpg.
--command-fd n
This is a replacement for the deprecated shared-memory
IPC mode. If this option is enabled, user input on
questions is not expected from the TTY but from the
given file descriptor. It should be used together with
--status-fd. See the file doc/DETAILS in the source
distribution for details on how to use it.
--command-file file
Same as --command-fd, except the commands are read out
of file file
--allow-non-selfsigned-uid
--no-allow-non-selfsigned-uid
Allow the import and use of keys with user IDs which
are not self-signed. This is not recommended, as a non
self-signed user ID is trivial to forge. --no-allow-
non-selfsigned-uid disables.
--allow-freeform-uid
Disable all checks on the form of the user ID while
generating a new one. This option should only be used
in very special environments as it does not ensure the
de-facto standard format of user IDs.
--ignore-time-conflict
GnuPG normally checks that the timestamps associated
with keys and signatures have plausible values. How-
ever, sometimes a signature seems to be older than the
key due to clock problems. This option makes these
checks just a warning. See also --ignore-valid-from for
timestamp issues on subkeys.
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--ignore-valid-from
GnuPG normally does not select and use subkeys created
in the future. This option allows the use of such keys
and thus exhibits the pre-1.0.7 behaviour. You should
not use this option unless you there is some clock
problem. See also --ignore-time-conflict for timestamp
issues with signatures.
--ignore-crc-error
The ASCII armor used by OpenPGP is protected by a CRC
checksum against transmission errors. Occasionally the
CRC gets mangled somewhere on the transmission channel
but the actual content (which is protected by the
OpenPGP protocol anyway) is still okay. This option
allows GnuPG to ignore CRC errors.
--ignore-mdc-error
This option changes a MDC integrity protection failure
into a warning. This can be useful if a message is
partially corrupt, but it is necessary to get as much
data as possible out of the corrupt message. However,
be aware that a MDC protection failure may also mean
that the message was tampered with intentionally by an
attacker.
--no-default-keyring
Do not add the default keyrings to the list of keyr-
ings. Note that GnuPG will not operate without any
keyrings, so if you use this option and do not provide
alternate keyrings via --keyring or --secret-keyring,
then GnuPG will still use the default public or secret
keyrings.
--skip-verify
Skip the signature verification step. This may be used
to make the decryption faster if the signature verifi-
cation is not needed.
--with-key-data
Print key listings delimited by colons (like --with-
colons) and print the public key data.
--fast-list-mode
Changes the output of the list commands to work faster;
this is achieved by leaving some parts empty. Some
applications don't need the user ID and the trust
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GNU Privacy Guard GPG2(1)
information given in the listings. By using this
options they can get a faster listing. The exact
behaviour of this option may change in future versions.
If you are missing some information, don't use this
option.
--no-literal
This is not for normal use. Use the source to see for
what it might be useful.
--set-filesize
This is not for normal use. Use the source to see for
what it might be useful.
--show-session-key
Display the session key used for one message. See --
override-session-key for the counterpart of this
option.
We think that Key Escrow is a Bad Thing; however the
user should have the freedom to decide whether to go to
prison or to reveal the content of one specific message
without compromising all messages ever encrypted for
one secret key. DON'T USE IT UNLESS YOU ARE REALLY
FORCED TO DO SO.
--override-session-key string
Don't use the public key but the session key string.
The format of this string is the same as the one
printed by --show-session-key. This option is normally
not used but comes handy in case someone forces you to
reveal the content of an encrypted message; using this
option you can do this without handing out the secret
key.
--ask-sig-expire
--no-ask-sig-expire
When making a data signature, prompt for an expiration
time. If this option is not specified, the expiration
time set via --default-sig-expire is used. --no-ask-
sig-expire disables this option. Note that by default,
--force-v3-sigs is set which also disables this option.
If you want signature expiration, you must set --no-
force-v3-sigs as well as turning --ask-sig-expire on.
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--default-sig-expire
The default expiration time to use for signature
expiration. Valid values are "0" for no expiration, a
number followed by the letter d (for days), w (for
weeks), m (for months), or y (for years) (for example
"2m" for two months, or "5y" for five years), or an
absolute date in the form YYYY-MM-DD. Defaults to "0".
--ask-cert-expire
--no-ask-cert-expire
When making a key signature, prompt for an expiration
time. If this option is not specified, the expiration
time set via --default-cert-expire is used. --no-ask-
cert-expire disables this option.
--default-cert-expire
The default expiration time to use for key signature
expiration. Valid values are "0" for no expiration, a
number followed by the letter d (for days), w (for
weeks), m (for months), or y (for years) (for example
"2m" for two months, or "5y" for five years), or an
absolute date in the form YYYY-MM-DD. Defaults to "0".
--allow-secret-key-import
This is an obsolete option and is not used anywhere.
--allow-multiple-messages
--no-allow-multiple-messages
Allow processing of multiple OpenPGP messages contained
in a single file or stream. Some programs that call
GPG are not prepared to deal with multiple messages
being processed together, so this option defaults to
no. Note that versions of GPG prior to 1.4.7 always
allowed multiple messages.
Warning: Do not use this option unless you need it as a
temporary workaround!
--enable-special-filenames
This options 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.
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--no-expensive-trust-checks
Experimental use only.
--preserve-permissions
Don't change the permissions of a secret keyring back
to user read/write only. Use this option only if you
really know what you are doing.
--default-preference-list string
Set the list of default preferences to string. This
preference list is used for new keys and becomes the
default for "setpref" in the edit menu.
--default-keyserver-url name
Set the default keyserver URL to name. This keyserver
will be used as the keyserver URL when writing a new
self-signature on a key, which includes key generation
and changing preferences.
--list-config
Display various internal configuration parameters of
GnuPG. This option is intended for external programs
that call GnuPG to perform tasks, and is thus not gen-
erally useful. See the file doc/DETAILS in the source
distribution for the details of which configuration
items may be listed. --list-config is only usable with
--with-colons set.
--gpgconf-list
This command is similar to --list-config but in general
only internally used by the gpgconf tool.
--gpgconf-test
This is more or less dummy action. However it parses
the configuration file and returns with failure if the
configuration file would prevent gpg from startup.
Thus it may be used to run a syntax check on the confi-
guration file.
Deprecated options
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--show-photos
--no-show-photos
Causes --list-keys, --list-sigs, --list-public-keys,
--list-secret-keys, and verifying a signature to also
display the photo ID attached to the key, if any. See
also --photo-viewer. These options are deprecated. Use
--list-options [no-]show-photos and/or --verify-options
[no-]show-photos instead.
--show-keyring
Display the keyring name at the head of key listings to
show which keyring a given key resides on. This option
is deprecated: use --list-options [no-]show-keyring
instead.
--always-trust
Identical to --trust-model always. This option is
deprecated.
--show-notation
--no-show-notation
Show signature notations in the --list-sigs or --
check-sigs listings as well as when verifying a signa-
ture with a notation in it. These options are depre-
cated. Use --list-options [no-]show-notation and/or --
verify-options [no-]show-notation instead.
--show-policy-url
--no-show-policy-url
Show policy URLs in the --list-sigs or --check-sigs
listings as well as when verifying a signature with a
policy URL in it. These options are deprecated. Use --
list-options [no-]show-policy-url and/or --verify-
options [no-]show-policy-url instead.
EXAMPLES
gpg -se -r Bob file
sign and encrypt for user Bob
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gpg --clearsign file
make a clear text signature
gpg -sb file
make a detached signature
gpg -u 0x12345678 -sb file
make a detached signature with the key 0x12345678
gpg --list-keys user_ID
show keys
gpg --fingerprint user_ID
show fingerprint
gpg --verify pgpfile
gpg --verify sigfile
Verify the signature of the file but do not output the
data. The second form is used for detached signatures,
where sigfile is the detached signature (either ASCII
armored or binary) and are the signed data; if this is
not given, the name of the file holding the signed data
is constructed by cutting off the extension (".asc" or
".sig") of sigfile or by asking the user for the
filename.
HOW TO SPECIFY A USER ID
There are different ways to specify a user ID to GnuPG.
Some of them are only valid for gpg others are only good for
gpgsm. Here is the entire list of ways to specify a key:
By key Id.
This format is deduced from the length of the string
and its content or 0x prefix. The key Id of an X.509
certificate are the low 64 bits of its SHA-1 finger-
print. The use of key Ids is just a shortcut, for all
automated processing the fingerprint should be used.
When using gpg an exclamation mark (!) may be appended
to force using the specified primary or secondary key
and not to try and calculate which primary or secondary
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key to use.
The last four lines of the example give the key ID in
their long form as internally used by the OpenPGP pro-
tocol. You can see the long key ID using the option --
with-colons.
234567C4
0F34E556E
01347A56A
0xAB123456
234AABBCC34567C4
0F323456784E56EAB
01AB3FED1347A5612
0x234AABBCC34567C4
By fingerprint.
This format is deduced from the length of the string
and its content or the 0x prefix. Note, that only the
20 byte version fingerprint is available with gpgsm
(i.e. the SHA-1 hash of the certificate).
When using gpg an exclamation mark (!) may be appended
to force using the specified primary or secondary key
and not to try and calculate which primary or secondary
key to use.
The best way to specify a key Id is by using the
fingerprint. This avoids any ambiguities in case that
there are duplicated key IDs.
1234343434343434C434343434343434
123434343434343C3434343434343734349A3434
0E12343434343434343434EAB3484343434343434
0xE12343434343434343434EAB3484343434343434
(gpgsm also accepts colons between each pair of hexadecimal
digits because this is the de-facto standard on how to
present X.509 fingerprints.)
By exact match on OpenPGP user
This is denoted by a leading equal sign. It does not
make sense for X.509 certificates.
=Heinrich Heine
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By exact match on an email
This is indicated by enclosing the email address in the
usual way with left and right angles.
By word match.
All words must match exactly (not case sensitive) but
can appear in any order in the user ID or a subjects
name. Words are any sequences of letters, digits, the
underscore and all characters with bit 7 set.
+Heinrich Heine duesseldorf
By exact match on the subject's
This is indicated by a leading slash, directly followed
by the RFC-2253 encoded DN of the subject. Note that
you can't use the string printed by "gpgsm --list-keys"
because that one as been reordered and modified for
better readability; use --with-colons to print the raw
(but standard escaped) RFC-2253 string
/CN=Heinrich Heine,O=Poets,L=Paris,C=FR
By exact match on the issuer's
This is indicated by a leading hash mark, directly fol-
lowed by a slash and then directly followed by the
rfc2253 encoded DN of the issuer. This should return
the Root cert of the issuer. See note above.
#/CN=Root Cert,O=Poets,L=Paris,C=FR
By exact match on serial number
This is indicated by a hash mark, followed by the hexa-
decimal representation of the serial number, then fol-
lowed by a slash and the RFC-2253 encoded DN of the
issuer. See note above.
#4F03/CN=Root Cert,O=Poets,L=Paris,C=FR
By keygrip
This is indicated by an ampersand followed by the 40
hex digits of a keygrip. gpgsm prints the keygrip when
using the command --dump-cert. It does not yet work
for OpenPGP keys.
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&D75F22C3F86E355877348498CDC92BD21010A480
By substring match.
This is the default mode but applications may want to
explicitly indicate this by putting the asterisk in
front. Match is not case sensitive.
Heine
*Heine
Please note that we have reused the hash mark identifier
which was used in old GnuPG versions to indicate the so
called local-id. It is not anymore used and there should be
no conflict when used with X.509 stuff.
Using the RFC-2253 format of DNs has the drawback that it is
not possible to map them back to the original encoding, how-
ever we don't have to do this because our key database
stores this encoding as meta data.
FILES
There are a few configuration files to control certain
aspects of gpg2's operation. Unless noted, they are expected
in the current home directory (see: [option --homedir]).
gpg.conf
This is the standard configuration file read by gpg2 on
startup. It may contain any valid long option; the
leading two dashes may not be entered and the option
may not be abbreviated. This default name may be
changed on the command line (see: [option --options]).
You should backup this file.
Note that on larger installations, it is useful to put
predefined files into the directory /etc/skel/.gnupg/ so
that newly created users start up with a working configura-
tion. For existing users the a small helper script is pro-
vided to create these files (see: [addgnupghome]).
For internal purposes gpg2 creates and maintains a few other
files; They all live in in the current home directory (see:
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[option --homedir]). Only the gpg2 may modify these files.
~/.gnupg/secring.gpg
The secret keyring. You should backup this file.
~/.gnupg/secring.gpg.lock
The lock file for the secret keyring.
~/.gnupg/pubring.gpg
The public keyring. You should backup this file.
~/.gnupg/pubring.gpg.lock
The lock file for the public keyring.
~/.gnupg/trustdb.gpg
The trust database. There is no need to backup this file;
it is better to backup the ownertrust values (see: [option
--export-ownertrust]).
~/.gnupg/trustdb.gpg.lock
The lock file for the trust database.
~/.gnupg/random_seed
A file used to preserve the state of the internal random
pool.
/usr[/local]/share/gnupg/options.skel
The skeleton options file.
/usr[/local]/lib/gnupg/
Default location for extensions.
Operation is further controlled by a few environment vari-
ables:
HOME
Used to locate the default home directory.
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GNUPGHOME
If set directory used instead of "~/.gnupg".
GPG_AGENT_INFO
Used to locate the gpg-agent. The value consists of 3 colon
delimited fields: The first is the path to the Unix Domain
Socket, the second the PID of the gpg-agent and the protocol
version which should be set to 1. When starting the gpg-
agent as described in its documentation, this variable is
set to the correct value. The option --gpg-agent-info can be
used to override it.
PINENTRY_USER_DATA
This value is passed via gpg-agent to pinentry. It is use-
ful to convey extra information to a custom pinentry.
COLUMNS
LINES
Used to size some displays to the full size of the screen.
LANGUAGE
Apart from its use by GNU, it is used in the W32 version to
override the language selection done through the Registry.
If used and set to a valid and available language name (lan-
gid), the file with the translation is loaded from
gpgdir/gnupg.nls/langid.mo. Here gpgdir is the directory
out of which the gpg binary has been loaded. If it can't be
loaded the Registry is tried and as last resort the native
Windows locale system is used.
BUGS
On many systems this program should be installed as
setuid(root). This is necessary to lock memory pages. Lock-
ing memory pages prevents the operating system from writing
memory pages (which may contain passphrases or other sensi-
tive material) to disk. If you get no warning message about
insecure memory your operating system supports locking
without being root. The program drops root privileges as
soon as locked memory is allocated.
Note also that some systems (especially laptops) have the
ability to ``suspend to disk'' (also known as ``safe sleep''
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or ``hibernate''). This writes all memory to disk before
going into a low power or even powered off mode. Unless
measures are taken in the operating system to protect the
saved memory, passphrases or other sensitive material may be
recoverable from it later.
SEE ALSO
gpgv(1), gpgsm(1), gpg-agent(1)
The full documentation for this tool is maintained as a Tex-
info manual. If GnuPG and the info program are properly
installed at your site, the command
info gnupg
should give you access to the complete manual including a
menu structure and an index.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
_______________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE|
|____________________|__________________|_
| Availability | crypto/gnupg |
|____________________|__________________|_
| Interface Stability| Uncommitted |
|____________________|_________________|
NOTES
Source for GnuPG is available at http://opensolaris.org and
at http://www.gnupg.org. Documentation is available at
file:///usr/share/man, and http://www.gnupg.org.
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