Linux "gpg" Command Line Options and Examples

OpenPGP encryption and signing tool

gpg is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a tool to provide digital encryption and signing services using the OpenPGP standard. gpg features complete key management and all the bells and whistles you would expect from a full OpenPGP implemen‐ tation.

Usage:

gpg [--homedir dir] [--options file] [options] command [args]

Related Commands

Command Line Options:

--default-key

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 secretkeyring. Note that -u or --local-user overrides this option. This option may be given multiple times. In this case, thelast key for which a secret key is available is used. If there is no secret key available for any of the specified values,GnuPG will not emit an error message but continue as if this option wasn't given.


                            gpg --default-key ...

--default-recipient

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.


                            gpg --default-recipient ...

--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 one. The defaultkey is the first one from the secret keyring or the one set with --default-key.


                            gpg --default-recipient-self ...

--no-default-recipient

Reset --default-recipient and --default-recipient-self.


                            gpg --no-default-recipient ...

-v

Give more information during processing. If used twice, the input data is listed in detail.


                            gpg -v ...

--no-verbose

Reset verbose level to 0.


                            gpg --no-verbose ...

-q

Try to be as quiet as possible.


                            gpg -q ...

--no-batch

Use batch mode. Never ask, do not allow interactive commands. --no-batch disables this option. Note that even with a file‐name given on the command line, gpg might still need to read from STDIN (in particular if gpg figures that the input is adetached signature and no data file has been specified). Thus if you do not want to feed data via STDIN, you should connectSTDIN to g‘/dev/null’.It is highly recommended to use this option along with the options --status-fd and --with-colons for any unattended use ofgpg.


                            gpg --no-batch ...

--no-tty

Make sure that the TTY (terminal) is never used for any output. This option is needed in some cases because GnuPG sometimesprints warnings to the TTY even if --batch is used.


                            gpg --no-tty ...

--yes

Assume "yes" on most questions.


                            gpg --yes ...

--no

Assume "no" on most questions.


                            gpg --no ...

--list-options

This is a space or comma delimited string that gives options used when listing keys and signatures (that is, --list-keys,


                            gpg --list-options ...

--check-signatures

no- (after the two dashes) to give the opposite meaning. The options are:show-photosCauses --list-keys, --check-signatures, --list-public-keys, and --list-secret-keys to display any photo IDs attached tothe key. Defaults to no. See also --photo-viewer. Does not work with --with-colons: see --attribute-fd for the appro‐priate way to get photo data for scripts and other frontends.show-usageShow usage information for keys and subkeys in the standard key listing. This is a list of letters indicating theallowed usage for a key (E=encryption, S=signing, C=certification, A=authentication). Defaults to yes.show-policy-urlsShow policy URLs in the --check-signatures listings. Defaults to no.show-notationsshow-std-notationsshow-user-notationsShow all, IETF standard, or user-defined signature notations in the --check-signatures listings. Defaults to no.show-keyserver-urlsShow any preferred keyserver URL in the --check-signatures listings. Defaults to no.show-uid-validityDisplay the calculated validity of user IDs during key listings. Defaults to yes.show-unusable-uidsShow revoked and expired user IDs in key listings. Defaults to no.show-unusable-subkeysShow revoked and expired subkeys in key listings. Defaults to no.show-keyringDisplay the keyring name at the head of key listings to show which keyring a given key resides on. Defaults to no.show-sig-expireShow signature expiration dates (if any) during --check-signatures listings. Defaults to no.show-sig-subpacketsInclude signature subpackets in the key listing. This option can take an optional argument list of the subpackets tolist. If no argument is passed, list all subpackets. Defaults to no. This option is only meaningful when using --with-colons along with --check-signatures.


                            gpg --check-signatures ...

--verify-options

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-photosDisplay any photo IDs present on the key that issued the signature. Defaults to no. See also --photo-viewer.show-policy-urlsShow policy URLs in the signature being verified. Defaults to yes.show-notationsshow-std-notationsshow-user-notationsShow all, IETF standard, or user-defined signature notations in the signature being verified. Defaults to IETF stan‐dard.show-keyserver-urlsShow any preferred keyserver URL in the signature being verified. Defaults to yes.show-uid-validityDisplay the calculated validity of the user IDs on the key that issued the signature. Defaults to yes.show-unusable-uidsShow revoked and expired user IDs during signature verification. Defaults to no.show-primary-uid-onlyShow only the primary user ID during signature verification. That is all the AKA lines as well as photo Ids are notshown with the signature verification status.pka-lookupsEnable PKA lookups to verify sender addresses. Note that PKA is based on DNS, and so enabling this option may discloseinformation 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 option.pka-trust-increaseRaise the trust in a signature to full if the signature passes PKA validation. This option is only meaningful if pka-lookups is set.


                            gpg --verify-options ...

--disable-large-rsa

With --generate-key and --batch, enable the creation of RSA secret keys as large as 8192 bit. Note: 8192 bit is more than isgenerally recommended. These large keys don't significantly improve security, but they are more expensive to use, and theirsignatures and certifications are larger. This option is only available if the binary was build with large-secmem support.


                            gpg --disable-large-rsa ...

--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. Notethat older versions of GnuPG also required this flag to allow the generation of DSA larger than 1024 bit.


                            gpg --disable-dsa2 ...

--photo-viewer

This is the command line that should be run to view a photo ID. "%i" will be expanded to a filename containing 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 thelong key ID, "%f" for the key fingerprint, "%t" for the extension of the image type (e.g. "jpg"), "%T" for the MIME type ofthe image (e.g. "image/jpeg"), "%v" for the single-character calculated validity of the image being viewed (e.g. "f"), "%V"for the calculated validity as a string (e.g. "full"), "%U" for a base32 encoded hash of the user ID, and "%%" for an actualpercent sign. If neither %i or %I are present, then the 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 notsecure, then executing it from GnuPG does not make it secure.


                            gpg --photo-viewer ...

--exec-path

Sets a list of directories to search for photo viewers and keyserver helpers. If not provided, keyserver helpers use the com‐piled-in default directory, and photo viewers use the PATH environment variable. Note, that on W32 system this value isignored when searching for keyserver helpers.


                            gpg --exec-path ...

--keyring

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 alongwith --no-default-keyring.If the option --no-keyring has been used no keyrings will be used at all.


                            gpg --keyring ...

--secret-keyring

This is an obsolete option and ignored. All secret keys are stored in the ‘private-keys-v1.d’ directory below the GnuPG homedirectory.


                            gpg --secret-keyring ...

--primary-keyring

Designate file as the primary public keyring. This means that newly imported keys (via --import or keyserver --recv-from) willgo to this keyring.


                            gpg --primary-keyring ...

--trustdb-name

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).


                            gpg --trustdb-name ...

--homedir

Set the name of the home directory to dir. If this option is not used, the home directory defaults to ‘~/.gnupg’. It is onlyrecognized when given on the command line. It also overrides any home directory stated through the environment variable‘GNUPGHOME’ or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option isconsidered, all other ways to set a home directory are ignored.To install GnuPG as a portable application under Windows, create an empty file named ‘gpgconf.ctl’ in the same directory asthe tool ‘gpgconf.exe’. The root of the installation is then that directory; or, if ‘gpgconf.exe’ has been installed directlybelow a directory named ‘bin’, its parent directory. You also need to make sure that the following directories exist and arewritable: ‘ROOT/home’ for the GnuPG home and ‘ROOT/var/cache/gnupg’ for internal cache files.


                            gpg --homedir ...

--display-charset

Set the name of the native character set. This is used to convert some informational strings like user IDs to the proper UTF-8encoding. Note that this has nothing to do with the character set of data to be encrypted or signed; GnuPG does not recodeuser-supplied data. If this option is not used, the default character set is determined from the current locale. A verbositylevel of 3 shows the chosen set. Valid values for name are:iso-8859-1This is the Latin 1 set.iso-8859-2The Latin 2 set.iso-8859-15This is currently an alias for the Latin 1 set.koi8-r The usual Russian set (RFC-1489).utf-8 Bypass all translations and assume that the OS uses native UTF-8 encoding.


                            gpg --display-charset ...

--no-utf8-strings

Assume that command line arguments are given as UTF-8 strings. The default (--no-utf8-strings) is to assume that arguments areencoded in the character set as specified by --display-charset. These options affect all following arguments. Both options maybe used multiple times.


                            gpg --no-utf8-strings ...

--options

Read options from file and do not try to read them from the default options file in the homedir (see --homedir). This optionis ignored if used in an options file.


                            gpg --options ...

--no-options

Shortcut for --options /dev/null. This option is detected before an attempt to open an option file. Using this option willalso prevent the creation of a ‘~/.gnupg’ homedir.


                            gpg --no-options ...

--bzip2-compress-level

Set compression level to n for the ZIP and ZLIB compression algorithms. The default is to use the default compression level ofzlib (normally 6). --bzip2-compress-level sets the compression level for the BZIP2 compression algorithm (defaulting to 6 aswell). This is a different option from --compress-level since BZIP2 uses a significant amount of memory for each additionalcompression level. -z sets both. A value of 0 for n disables compression.


                            gpg --bzip2-compress-level ...

--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 compressedat a high --bzip2-compress-level.


                            gpg --bzip2-decompress-lowmem ...

--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 noeffect on non-Windows platforms.


                            gpg --no-mangle-dos-filenames ...

--no-ask-cert-level

When making a key signature, prompt for a certification level. If this option is not specified, the certification level usedis set via --default-cert-level. See --default-cert-level for information on the specific levels and how they are used. --no-ask-cert-level disables this option. This option defaults to no.


                            gpg --no-ask-cert-level ...

--default-cert-level

The default to use for the check level when signing a key.0 means you make no particular claim as to how carefully 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" verification, 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 the key fingerprint and checkedthe 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 theowner 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 ofemail) 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).


                            gpg --default-cert-level ...

--min-cert-level

When building the trust database, treat any signatures with a certification level below this as invalid. Defaults to 2, whichdisregards level 1 signatures. Note that level 0 "no particular claim" signatures are always accepted.


                            gpg --min-cert-level ...

--trusted-key

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 checkthe validity of a given recipient's or signator's key.


                            gpg --trusted-key ...

--trust-model

Set what trust model GnuPG should follow. The models are:pgp This is the Web of Trust combined with trust signatures as used in PGP 5.x and later. This is the default trust modelwhen creating a new trust database.classicThis is the standard Web of Trust as introduced by PGP 2.tofuTOFU stands for Trust On First Use. In this trust model, the first time a key is seen, it is memorized. If lateranother key with a user id with the same email address is seen, both keys are marked as suspect. In that case, thenext time either is used, a warning is displayed describing the conflict, why it might have occurred (either the usergenerated a new key and failed to cross sign the old and new keys, the key is forgery, or a man-in-the-middle attack isbeing attempted), and the user is prompted to manually confirm the validity of the key in question.Because a potential attacker is able to control the email address and thereby circumvent the conflict detection algo‐rithm by using an email address that is similar in appearance to a trusted email address, whenever a message is veri‐fied, statistics about the number of messages signed with the key are shown. In this way, a user can easily identifyattacks using fake keys for regular correspondents.When compared with the Web of Trust, TOFU offers significantly weaker security guarantees. In particular, TOFU onlyhelps ensure consistency (that is, that the binding between a key and email address doesn't change). A major advantageof TOFU is that it requires little maintenance to use correctly. To use the web of trust properly, you need toactively sign keys and mark users as trusted introducers. This is a time-consuming process and anecdotal evidence sug‐gests that even security-conscious users rarely take the time to do this thoroughly and instead rely on an ad-hoc TOFUprocess.In the TOFU model, policies are associated with bindings between keys and email addresses (which are extracted fromuser ids and normalized). There are five policies, which can be set manually using the --tofu-policy option. Thedefault policy can be set using the --tofu-default-policy option.The TOFU policies are: auto, good, unknown, bad and ask. The auto policy is used by default (unless overridden by


                            gpg --trust-model ...

--no-auto-key-locate

GnuPG can automatically locate and retrieve keys as needed using this option. This happens when encrypting to an emailaddress (in the "user@example.com" form), and there are no "user@example.com" keys on the local keyring. This option takesany number of the mechanisms listed below, in the order they are to be tried. Instead of listing the mechanisms as commadelimited arguments, the option may also be given several times to add more mechanism. The option --no-auto-key-locate or themechanism "clear" resets the list. The default is "local,wkd".cert Locate a key using DNS CERT, as specified in RFC-4398.pka Locate a key using DNS PKA.dane Locate a key using DANE, as specified in draft-ietf-dane-openpgpkey-05.txt.wkd Locate a key using the Web Key Directory protocol.ldap Using DNS Service Discovery, check the domain in question for any LDAP keyservers to use. If this fails, attempt tolocate the key using the PGP Universal method of checking 'ldap://keys.(thedomain)'.keyserverLocate a key using whatever keyserver is defined using the --keyserver option.keyserver-URLIn 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 the user to select the order a local key lookup isdone. Thus using '--auto-key-locate local' is identical to --no-auto-key-locate.nodefaultThis flag disables the standard local key lookup, done before any of the mechanisms defined by the --auto-key-locateare tried. The position of this mechanism in the list does not matter. It is not required if local is also used.clear Clear all defined mechanisms. This is useful to override mechanisms given in a config file.


                            gpg --no-auto-key-locate ...

--no-auto-key-retrieve

These options enable or disable the automatic retrieving of keys from a keyserver when verifying signatures made by keys thatare not on the local keyring. The default is --no-auto-key-retrieve.If the method "wkd" is included in the list of methods given to auto-key-locate, the signer's user ID is part of the signa‐ture, and the option --disable-signer-uid is not used, the "wkd" method may also be used to retrieve a key.Note that this option makes a "web bug" like behavior possible. Keyserver or Web Key Directory operators can see which keysyou request, so by sending you a message signed by a brand new key (which you naturally will not have on your local keyring),the operator can tell both your IP address and the time when you verified the signature.


                            gpg --no-auto-key-retrieve ...

--keyid-format

Select how to display key IDs. "none" does not show the key ID at all but shows the fingerprint in a separate line. "short"is the traditional 8-character key ID. "long" is the more accurate (but less convenient) 16-character key ID. Add an "0x" toeither to include an "0x" at the beginning of the key ID, as in 0x99242560. Note that this option is ignored if the option


                            gpg --keyid-format ...

--keyserver

This option is deprecated - please use the --keyserver in ‘dirmngr.conf’ instead.Use name as your keyserver. This is the server that --receive-keys, --send-keys, and --search-keys will communicate with toreceive 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 particular installation of GnuPG may have other keyserver types avail‐able as well. Keyserver schemes are case-insensitive. After the keyserver name, optional keyserver configuration options maybe 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 keyserverhkp://keys.gnupg.net uses round robin DNS to give a different keyserver each time you use it.


                            gpg --keyserver ...

--keyserver-options

This is a space or comma delimited string that gives options for the keyserver. Options can be prefixed with a `no-' to givethe opposite meaning. Valid import-options or export-options may be used here as well to apply to importing (--recv-key) orexporting (--send-key) a key from a keyserver. While not all options are available for all keyserver types, some commonoptions are:include-revokedWhen searching for a key with --search-keys, include keys that are marked on the keyserver as revoked. Note that notall keyservers differentiate between revoked and unrevoked keys, and for such keyservers this option is meaningless.Note also that most keyservers do not have cryptographic verification of key revocations, and so turning this optionoff may result in skipping keys that are incorrectly marked as revoked.include-disabledWhen searching for a key with --search-keys, include keys that are marked on the keyserver as disabled. Note that thisoption is not used with HKP keyservers.auto-key-retrieveThis is an obsolete alias for the option auto-key-retrieve. Please do not use it; it will be removed in future ver‐sions..honor-keyserver-urlWhen using --refresh-keys, if the key in question has a preferred keyserver URL, then use that preferred keyserver torefresh the key from. In addition, if auto-key-retrieve is set, and the signature being verified has a preferred key‐server URL, then use that preferred keyserver to fetch the key from. Note that this option introduces a "web bug": Thecreator of the key can see when the keys is refreshed. Thus this option is not enabled by default.honor-pka-recordIf --auto-key-retrieve is used, and the signature being verified has a PKA record, then use the PKA information tofetch the key. Defaults to "yes".include-subkeysWhen receiving a key, include subkeys as potential targets. Note that this option is not used with HKP keyservers, asthey do not support retrieving keys by subkey id.timeoutTell the keyserver helper program how long (in seconds) to try and perform a keyserver action before giving up. Notethat performing multiple actions at the same time uses this timeout value per action. For example, when retrievingmultiple keys via --receive-keys, the timeout applies separately to each key retrieval, and not to the --receive-keyscommand as a whole. Defaults to 30 seconds.http-proxy=valueThis option is deprecated. Set the proxy to use for HTTP and HKP keyservers. This overrides any proxy defined in‘dirmngr.conf’.verboseThis option has no more function since GnuPG 2.1. Use the dirmngr configuration options instead.debug This option has no more function since GnuPG 2.1. Use the dirmngr configuration options instead.check-certThis option has no more function since GnuPG 2.1. Use the dirmngr configuration options instead.ca-cert-fileThis option has no more function since GnuPG 2.1. Use the dirmngr configuration options instead.


                            gpg --keyserver-options ...

--completes-needed

Number of completely trusted users to introduce a new key signer (defaults to 1).


                            gpg --completes-needed ...

--marginals-needed

Number of marginally trusted users to introduce a new key signer (defaults to 3)


                            gpg --marginals-needed ...

--tofu-default-policy

The default TOFU policy (defaults to auto). For more information about the meaning of this option, see: [trust-model-tofu].


                            gpg --tofu-default-policy ...

--max-cert-depth

Maximum depth of a certification chain (default is 5).


                            gpg --max-cert-depth ...

--no-sig-cache

Do not cache the verification status of key signatures. Caching gives a much better performance in key listings. However, ifyou suspect that your public keyring is not safe 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 yourpublic keyring.


                            gpg --no-sig-cache ...

--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 com‐mand internally. This may be a time consuming process. --no-auto-check-trustdb disables this option.


                            gpg --no-auto-check-trustdb ...

--no-use-agent

This is dummy option. gpg always requires the agent.


                            gpg --no-use-agent ...

--gpg-agent-info

This is dummy option. It has no effect when used with gpg.


                            gpg --gpg-agent-info ...

--agent-program

Specify an agent program to be used for secret key operations. The default value is determined by running gpgconf with theoption --list-dirs. Note that the pipe symbol (|) is used for a regression test suite hack and may thus not be used in thefile name.


                            gpg --agent-program ...

--dirmngr-program

Specify a dirmngr program to be used for keyserver access. The default value is ‘/usr/bin/dirmngr’.


                            gpg --dirmngr-program ...

--disable-dirmngr

Entirely disable the use of the Dirmngr.


                            gpg --disable-dirmngr ...

--no-autostart

Do not start the gpg-agent or the dirmngr if it has not yet been started and its service is required. This option is mostlyuseful on machines where the connection to gpg-agent has been redirected to another machines. If dirmngr is required on theremote machine, it may be started manually using gpgconf --launch dirmngr.


                            gpg --no-autostart ...

--lock-once

Lock the databases the first time a lock is requested and do not release the lock until the process terminates.


                            gpg --lock-once ...

--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.


                            gpg --lock-multiple ...

--lock-never

Disable locking entirely. This option should be used only in very special environments, where it can be assured that only oneprocess is accessing those files. A bootable floppy with a stand-alone encryption system will probably use this. Improperusage of this option may lead to data and key corruption.


                            gpg --lock-never ...

--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 defaultbut it never worked this way and thus we need an option to enable this, so that the change won't break applications whichclose their end of a status fd connected pipe too early. Using this option along with --enable-progress-filter may be used tocleanly cancel long running gpg operations.


                            gpg --exit-on-status-write-error ...

--limit-card-insert-tries

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'tat all ask to insert a card if none has been inserted at startup. This option is useful in the configuration file in case anapplication does not know about the smartcard support and waits ad infinitum for an inserted card.


                            gpg --limit-card-insert-tries ...

--no-random-seed-file

GnuPG uses a file to store its internal random pool over invocations. This makes random generation faster; however sometimeswrite operations are not desired. This option can be used to achieve that with the cost of slower random generation.


                            gpg --no-random-seed-file ...

--no-greeting

Suppress the initial copyright message.


                            gpg --no-greeting ...

--no-secmem-warning

Suppress the warning about "using insecure memory".


                            gpg --no-secmem-warning ...

--no-permission-warning

Suppress the warning about unsafe file and home directory (--homedir) permissions. Note that the permission checks that GnuPGperforms are not intended to be authoritative, but rather they simply warn about certain common permission problems. Do notassume 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 anattacker to place an unsafe gpg.conf file in place, and use this file to suppress warnings about itself. The --homedir permis‐sions warning may only be suppressed on the command line.


                            gpg --no-permission-warning ...

--no-require-secmem

Refuse to run if GnuPG cannot get secure memory. Defaults to no (i.e. run, but give a warning).


                            gpg --no-require-secmem ...

--no-require-cross-certification

When verifying a signature made from a subkey, ensure that the cross certification "back signature" on the subkey is presentand valid. This protects against a subtle attack against subkeys that can sign. Defaults to --require-cross-certificationfor gpg.


                            gpg --no-require-cross-certification ...

--no-expert

Allow the user to do certain nonsensical or "silly" things like signing an expired or revoked key, or certain potentiallyincompatible things like generating unusual key types. This also disables certain warning messages about potentially incompat‐ible actions. As the name implies, this option is for experts only. If you don't fully understand the implications of what itallows you to do, leave this off. --no-expert disables this option.Key related options


                            gpg --no-expert ...

--encrypt-to

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.


                            gpg --encrypt-to ...

--hidden-encrypt-to

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 ahidden "encrypt-to-self". These keys are only used when there are other recipients given either by use of --recipient or bythe asked user id. No trust checking is performed for these user ids and even disabled keys can be used.


                            gpg --hidden-encrypt-to ...

--no-encrypt-to

Disable the use of all --encrypt-to and --hidden-encrypt-to keys.


                            gpg --no-encrypt-to ...

--group

Sets up a named group, which is similar to aliases in email programs. Any time the group name is a recipient (-r or --recipi‐ent), it will be expanded to the values specified. Multiple groups with the same name are automatically merged into a singlegroup.The values are key IDs or fingerprints, but any key description is accepted. Note that a value with spaces in it will betreated as two different values. Note also there is only one level of expansion --- you cannot make an group that points toanother group. When used from the command line, it may be necessary to quote the argument to this option to prevent the shellfrom treating it as multiple arguments.


                            gpg --group ...

--ungroup

Remove a given entry from the --group list.


                            gpg --ungroup ...

--no-groups

Remove all entries from the --group list.


                            gpg --no-groups ...

-u

Use name as the key to sign with. Note that this option overrides --default-key.


                            gpg -u ...

--sender

This option has two purposes. mbox must either be a complete user id with a proper mail address or just a mail address. Whencreating a signature this option tells gpg the user id of a key used to make a signature if the key was not directly specifiedby a user id. When verifying a signature the mbox is used to restrict the information printed by the TOFU code to matchinguser ids.


                            gpg --sender ...

--try-secret-key

For hidden recipients GPG needs to know the keys to use for trial decryption. The key set with --default-key is always triedfirst, but this is often not sufficient. This option allows setting more keys to be used for trial decryption. Although anyvalid user-id specification may be used for name it makes sense to use at least the long keyid to avoid ambiguities. Notethat gpg-agent might pop up a pinentry for a lot keys to do the trial decryption. If you want to stop all further trialdecryption you may use close-window button instead of the cancel button.


                            gpg --try-secret-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 decryption key. Thisoption forces the behaviour as used by anonymous recipients (created by using --throw-keyids or --hidden-recipient) and mightcome handy in case where an encrypted message contains a bogus key ID.


                            gpg --try-all-secrets ...

--no-skip-hidden-recipients

During decryption skip all anonymous recipients. This option helps in the case that people use the hidden recipients featureto hide there own encrypt-to key from others. If oneself has many secret keys this may lead to a major annoyance because allkeys are tried in turn to decrypt something which was not really intended for it. The drawback of this option is that it iscurrently not possible to decrypt a message which includes real anonymous recipients.Input and Output


                            gpg --no-skip-hidden-recipients ...

-a

Create ASCII armored output. The default is to create the binary OpenPGP format.


                            gpg -a ...

--no-armor

Assume the input data is not in ASCII armored format.


                            gpg --no-armor ...

-o

Write output to file. To write to stdout use - as the filename.


                            gpg -o ...

--max-output

This option sets a limit on the number of bytes that will be generated when processing a file. Since OpenPGP supports variouslevels of compression, it is possible that the plaintext of a given message may be significantly larger than the originalOpenPGP message. While GnuPG works properly with such messages, there is often a desire to set a maximum file size that willbe generated before processing is forced to stop by the OS limits. Defaults to 0, which means "no limit".


                            gpg --max-output ...

--input-size-hint

This option can be used to tell GPG the size of the input data in bytes. n must be a positive base-10 number. This option isonly useful if the input is not taken from a file. GPG may use this hint to optimize its buffer allocation strategy. It isalso used by the --status-fd line ``PROGRESS'' to provide a value for ``total'' if that is not available by other means.


                            gpg --input-size-hint ...

--key-origin

gpg can track the origin of a key. Certain origins are implicitly known (e.g. keyserver, web key directory) and set. For astandard import the origin of the keys imported can be set with this option. To list the possible values use "help" forstring. Some origins can store an optional url argument. That URL can appended to string after a comma.


                            gpg --key-origin ...

--import-options

This is a space or comma delimited string that gives options for importing keys. Options can be prepended with a `no-' to givethe opposite meaning. The options are:import-local-sigsAllow importing key signatures marked as "local". This is not generally useful unless a shared keyring scheme is beingused. Defaults to no.keep-ownertrustNormally possible still existing ownertrust values of a key are cleared if a key is imported. This is in generaldesirable so that a formerly deleted key does not automatically gain an ownertrust values merely due to import. On theother hand it is sometimes necessary to re-import a trusted set of keys again but keeping already assigned ownertrustvalues. This can be achieved by using this option.repair-pks-subkey-bugDuring import, attempt to repair the damage caused by the PKS keyserver bug (pre version 0.9.6) that mangles keys withmultiple subkeys. Note that this cannot completely repair the damaged key as some crucial data is removed by the key‐server, but it does at least give you back one subkey. Defaults to no for regular --import and to yes for keyserver


                            gpg --import-options ...

--receive-keys.

import-showshow-onlyShow a listing of the key as imported right before it is stored. This can be combined with the option --dry-run toonly look at keys; the option show-only is a shortcut for this combination. Note that suffixes like '#' for "sec" and"sbb" lines may or may not be printed.import-exportRun the entire import code but instead of storing the key to the local keyring write it to the output. The exportoptions export-pka and export-dane affect the output. This option can be used to remove all invalid parts from a keywithout the need to store it.merge-onlyDuring import, allow key updates to existing keys, but do not allow any new keys to be imported. Defaults to no.import-cleanAfter import, compact (remove all signatures except the self-signature) any user IDs from the new key that are notusable. Then, remove any signatures from the new key that are not usable. This includes signatures that were issuedby keys that are not present on the keyring. This option is the same as running the --edit-key command "clean" afterimport. Defaults to no.repair-keys. After import, fix various problems with thekeys. For example, this reorders signatures, and strips duplicate signatures. Defaults to yes.import-minimalImport the smallest key possible. This removes all signatures except the most recent self-signature on each user ID.This option is the same as running the --edit-key command "minimize" after import. Defaults to no.restoreimport-restoreImport in key restore mode. This imports all data which is usually skipped during import; including all GnuPG specificdata. All other contradicting options are overridden.


                            gpg --receive-keys. ...

--export-filter

These options define an import/export filter which are applied to the imported/exported keyblock right before it will bestored/written. name defines the type of filter to use, expr the expression to evaluate. The option can be used severaltimes which then appends more expression to the same name.The available filter types are:keep-uidThis filter will keep a user id packet and its dependent packets in the keyblock if the expression evaluates to true.drop-subkeyThis filter drops the selected subkeys. Currently only implemented for --export-filter.drop-sigThis filter drops the selected key signatures on user ids. Self-signatures are not considered. Currently only imple‐mented for --import-filter.For the syntax of the expression see the chapter "FILTER EXPRESSIONS". The property names for the expressions depend on the actualfilter type and are indicated in the following table.The available properties are:uid A string with the user id. (keep-uid)mbox The addr-spec part of a user id with mailbox or the empty string. (keep-uid)key_algoA number with the public key algorithm of a key or subkey packet. (drop-subkey)key_createdkey_created_dThe first is the timestamp a public key or subkey packet was created. The second is the same but given as an ISOstring, e.g. "2016-08-17". (drop-subkey)primaryBoolean indicating whether the user id is the primary one. (keep-uid)expiredBoolean indicating whether a user id (keep-uid), a key (drop-subkey), or a signature (drop-sig) expired.revokedBoolean indicating whether a user id (keep-uid) or a key (drop-subkey) has been revoked.disabledBoolean indicating whether a primary key is disabled. (not used)secret Boolean indicating whether a key or subkey is a secret one. (drop-subkey)sig_createdsig_created_dThe first is the timestamp a signature packet was created. The second is the same but given as an ISO date string,e.g. "2016-08-17". (drop-sig)sig_algoA number with the public key algorithm of a signature packet. (drop-sig)sig_digest_algoA number with the digest algorithm of a signature packet. (drop-sig)


                            gpg --export-filter ...

--export-options

This is a space or comma delimited string that gives options for exporting keys. Options can be prepended with a `no-' togive the opposite meaning. The options are:export-local-sigsAllow exporting key signatures marked as "local". This is not generally useful unless a shared keyring scheme is beingused. Defaults to no.export-attributesInclude attribute user IDs (photo IDs) while exporting. Not including attribute user IDs is useful to export keys thatare going to be used by an OpenPGP program that does not accept attribute user IDs. Defaults to yes.export-sensitive-revkeysInclude designated revoker information that was marked as "sensitive". Defaults to no.backupexport-backupExport for use as a backup. The exported data includes all data which is needed to restore the key or keys later withGnuPG. The format is basically the OpenPGP format but enhanced with GnuPG specific data. All other contradictingoptions are overridden.export-cleanCompact (remove all signatures from) user IDs on the key being exported if the user IDs are not usable. Also, do notexport any signatures that are not usable. This includes signatures that were issued by keys that are not present onthe keyring. This option is the same as running the --edit-key command "clean" before export except that the local copyof the key is not modified. Defaults to no.export-minimalExport the smallest key possible. This removes all signatures except the most recent self-signature on each user ID.This option is the same as running the --edit-key command "minimize" before export except that the local copy of thekey is not modified. Defaults to no.export-pkaInstead of outputting the key material output PKA records suitable to put into DNS zone files. An ORIGIN line isprinted before each record to allow diverting the records to the corresponding zone file.export-daneInstead of outputting the key material output OpenPGP DANE records suitable to put into DNS zone files. An ORIGIN lineis printed before each record to allow diverting the records to the corresponding zone file.


                            gpg --export-options ...

--with-colons

Print key listings delimited by colons. Note that the output will be encoded in UTF-8 regardless of any --display-charset set‐ting. This format is useful when GnuPG is called from scripts and other programs as it is easily machine parsed. The detailsof this format are documented in the file ‘doc/DETAILS’, which is included in the GnuPG source distribution.


                            gpg --with-colons ...

--fixed-list-mode

Do not merge primary user ID and primary key in --with-colon listing mode and print all timestamps as seconds since1970-01-01. Since GnuPG 2.0.10, this mode is always used and thus this option is obsolete; it does not harm to use it though.


                            gpg --fixed-list-mode ...

--legacy-list-mode

Revert to the pre-2.1 public key list mode. This only affects the human readable output and not the machine interface (i.e.


                            gpg --legacy-list-mode ...

--with-colons).

Note that the legacy format does not convey suitable information for elliptic curves.


                            gpg --with-colons). ...

--with-fingerprint

Same as the command --fingerprint but changes only the format of the output and may be used together with another command.


                            gpg --with-fingerprint ...

--with-subkey-fingerprint

If a fingerprint is printed for the primary key, this option forces printing of the fingerprint for all subkeys. This couldalso be achieved by using the --with-fingerprint twice but by using this option along with keyid-format "none" a compact fin‐gerprint is printed.


                            gpg --with-subkey-fingerprint ...

--with-icao-spelling

Print the ICAO spelling of the fingerprint in addition to the hex digits.


                            gpg --with-icao-spelling ...

--with-keygrip

Include the keygrip in the key listings. In --with-colons mode this is implicitly enable for secret keys.


                            gpg --with-keygrip ...

--with-key-origin

Include the locally held information on the origin and last update of a key in a key listing. In --with-colons mode this isalways printed. This data is currently experimental and shall not be considered part of the stable API.


                            gpg --with-key-origin ...

--with-wkd-hash

Print a Web Key Directory identifier along with each user ID in key listings. This is an experimental feature and semanticsmay change.


                            gpg --with-wkd-hash ...

--with-secret

Include info about the presence of a secret key in public key listings done with --with-colons.OpenPGP protocol specific options


                            gpg --with-secret ...

--no-textmode

Treat input files as text and store them in the OpenPGP canonical text form with standard "CRLF" line endings. This also setsthe necessary flags to inform the recipient that the encrypted or signed data is text and may need its line endings convertedback to whatever the local system uses. This option is useful when communicating between two platforms that have differentline ending conventions (UNIX-like to Mac, Mac to Windows, etc). --no-textmode disables this option, and is the default.


                            gpg --no-textmode ...

--no-force-v4-certs

These options are obsolete and have no effect since GnuPG 2.1.


                            gpg --no-force-v4-certs ...

--disable-mdc

These options are obsolete and have no effect since GnuPG 2.2.4-1ubuntu1.1. The +MDC is always used. But note: If the cre‐ation of a legacy non-MDC message is exceptionally required, the option --rfc2440 allows for this.


                            gpg --disable-mdc ...

--disable-signer-uid

By default the user ID of the signing key is embedded in the data signature. As of now this is only done if the signing keyhas been specified with local-user using a mail address. This information can be helpful for verifier to locate the key; seeoption --auto-key-retrieve.


                            gpg --disable-signer-uid ...

--personal-cipher-preferences

Set the list of personal cipher preferences to string. Use gpg --version to get a list of available algorithms, and use noneto 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 alsoused for the --symmetric encryption command.


                            gpg --personal-cipher-preferences ...

--personal-digest-preferences

Set the list of personal digest preferences to string. Use gpg --version to get a list of available algorithms, and use noneto 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 listis also used when signing without encryption (e.g. --clear-sign or --sign).


                            gpg --personal-digest-preferences ...

--personal-compress-preferences

Set the list of personal compression preferences to string. Use gpg --version to get a list of available algorithms, and usenone to set no preference at all. This allows the user to safely override the algorithm chosen by the recipient key prefer‐ences, as GPG will only select an algorithm that is usable by all recipients. The most highly ranked compression algorithm inthis list is also used when there are no recipient keys to consider (e.g. --symmetric).


                            gpg --personal-compress-preferences ...

--s2k-cipher-algo

Use name as the cipher algorithm for symmetric encryption with a passphrase if --personal-cipher-preferences and --cipher-algoare not given. The default is AES-128.


                            gpg --s2k-cipher-algo ...

--s2k-digest-algo

Use name as the digest algorithm used to mangle the passphrases for symmetric encryption. The default is SHA-1.


                            gpg --s2k-digest-algo ...

--s2k-mode

Selects how passphrases for symmetric encryption are mangled. If n is 0 a plain passphrase (which is in general not recom‐mended) will be used, a 1 adds a salt (which should not be used) to the passphrase and a 3 (the default) iterates the wholeprocess a number of times (see --s2k-count).


                            gpg --s2k-mode ...

--s2k-count

Specify how many times the passphrases mangling for symmetric encryption is repeated. This value may range between 1024 and65011712 inclusive. The default is inquired from gpg-agent. Note that not all values in the 1024-65011712 range are legaland if an illegal value is selected, GnuPG will round up to the nearest legal value. This option is only meaningful if --s2k-mode is set to the default of 3.Compliance optionsThese options control what GnuPG is compliant to. Only one of these options may be active at a time. Note that the default setting ofthis is nearly always the correct one. See the INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS section below before using one of theseoptions.


                            gpg --s2k-count ...

--gnupg

Use standard GnuPG behavior. This is essentially OpenPGP behavior (see --openpgp), but with some additional workarounds forcommon compatibility problems in different versions of PGP. This is the default option, so it is not generally needed, but itmay be useful to override a different compliance option in the gpg.conf file.


                            gpg --gnupg ...

--openpgp

Reset all packet, cipher and digest options to strict OpenPGP behavior. Use this option to reset all previous options like


                            gpg --openpgp ...

--s2k-*

--cipher-algo --digest-algo and --compress-algo to OpenPGP compliant values. All PGP workarounds are disabled.


                            gpg --s2k-* ...

--rfc4880

Reset all packet, cipher and digest options to strict RFC-4880 behavior. Note that this is currently the same thing as


                            gpg --rfc4880 ...

--rfc4880bis

Enable experimental features from proposed updates to RFC-4880. This option can be used in addition to the other complianceoptions. Warning: The behavior may change with any GnuPG release and created keys or data may not be usable with future GnuPGversions.


                            gpg --rfc4880bis ...

--rfc2440

Reset all packet, cipher and digest options to strict RFC-2440 behavior. Note that by using this option encryption packetsare created in a legacy mode without MDC protection. This is dangerous and should thus only be used for experiments. Seealso option --ignore-mdc-error.


                            gpg --rfc2440 ...

--compliance

This option can be used instead of one of the options above. Valid values for string are the above option names (without thedouble dash) and possibly others as shown when using "help" for value.Doing things one usually doesn't want to do


                            gpg --compliance ...

--dry-run

Don't make any changes (this is not completely implemented).


                            gpg --dry-run ...

--list-only

Changes the behaviour of some commands. This is like --dry-run but different in some cases. The semantic of this option may beextended in the future. Currently it only skips the actual decryption pass and therefore enables a fast listing of the encryp‐tion keys.


                            gpg --list-only ...

--interactive

Prompt before overwriting any files.


                            gpg --interactive ...

--debug-level

Select the debug level for investigating problems. level may be a numeric value or by a keyword:none No debugging at all. A value of less than 1 may be used instead of the keyword.basic Some basic debug messages. A value between 1 and 2 may be used instead of the keyword.advancedMore verbose debug messages. A value between 3 and 5 may be used instead of the keyword.expert Even more detailed messages. A value between 6 and 8 may be used instead of the keyword.guru All of the debug messages you can get. A value greater than 8 may be used instead of the keyword. The creation of hashtracing files is only enabled if the keyword is used.How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. Theyare however carefully selected to best aid in debugging.


                            gpg --debug-level ...

--debug

Set debugging flags. All flags are or-ed and flags may be given in C syntax (e.g. 0x0042) or as a comma separated list of flagnames. To get a list of all supported flags the single word "help" can be used.


                            gpg --debug ...

--debug-all

Set all useful debugging flags.


                            gpg --debug-all ...

--debug-iolbf

Set stdout into line buffered mode. This option is only honored when given on the command line.


                            gpg --debug-iolbf ...

--faked-system-time

This option is only useful for testing; it sets the system time back or forth to epoch which is the number of seconds elapsedsince the year 1970. Alternatively epoch may be given as a full ISO time string (e.g. "20070924T154812").If you suffix epoch with an exclamation mark (!), the system time will appear to be frozen at the specified time.


                            gpg --faked-system-time ...

--enable-progress-filter

Enable certain PROGRESS status outputs. This option allows frontends to display a progress indicator while gpg is processinglarger files. There is a slight performance overhead using it.


                            gpg --enable-progress-filter ...

--status-fd

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


                            gpg --status-fd ...

--status-file

Same as --status-fd, except the status data is written to file file.


                            gpg --status-file ...

--logger-fd

Write log output to file descriptor n and not to STDERR.


                            gpg --logger-fd ...

--logger-file

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


                            gpg --logger-file ...

--attribute-fd

Write attribute subpackets to the file descriptor n. This is most useful for use with --status-fd, since the status messagesare needed to separate out the various subpackets from the stream delivered to the file descriptor.


                            gpg --attribute-fd ...

--attribute-file

Same as --attribute-fd, except the attribute data is written to file file.


                            gpg --attribute-file ...

--no-comments

Use string as a comment string in cleartext signatures and ASCII armored messages or keys (see --armor). The default behavioris not to use a comment string. --comment may be repeated multiple times to get multiple comment strings. --no-commentsremoves all comments. It is a good idea to keep the length of a single comment below 60 characters to avoid problems withmail programs wrapping such lines. Note that comment lines, like all other header lines, are not protected by the signature.


                            gpg --no-comments ...

--no-emit-version

Force inclusion of the version string in ASCII armored output. If given once only the name of the program and the major num‐ber is emitted, given twice the minor is also emitted, given thrice the micro is added, and given four times an operating sys‐tem identification is also emitted. --no-emit-version (default) disables the version line.


                            gpg --no-emit-version ...

-N

Put the name value pair into the signature as notation data. name must consist only of printable characters or spaces, andmust contain a '@' character in the form keyname@domain.example.com (substituting the appropriate keyname and domain name, ofcourse). This is to help prevent pollution of the IETF reserved notation namespace. The --expert flag overrides the '@'check. value may be any printable string; it will be encoded in UTF-8, so you should check that your --display-charset is setcorrectly. If you prefix name with an exclamation mark (!), the notation data will be flagged as critical (rfc4880:5.2.3.16).


                            gpg -N ...

--sig-notation

sets a notation for data signatures. --cert-notation sets a notation for key signatures (certifications).


                            gpg --sig-notation ...

--set-notation

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 ofthe key making the signature, "%S" into the long key ID of the key making the signature, "%g" into the fingerprint of the keymaking 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 single "%". %k, %K, and %f are only meaningfulwhen making a key signature (certification), and %c is only meaningful when using the OpenPGP smartcard.


                            gpg --set-notation ...

--set-policy-url

Use string as a Policy URL for signatures (rfc4880:5.2.3.20). If you prefix it with an exclamation mark (!), the policy URLpacket will be flagged as critical. --sig-policy-url sets a policy url for data signatures. --cert-policy-url sets a policyurl for key signatures (certifications). --set-policy-url sets both.The same %-expandos used for notation data are available here as well.


                            gpg --set-policy-url ...

--sig-keyserver-url

Use string as a preferred keyserver URL for data signatures. If you prefix it with an exclamation mark (!), the keyserver URLpacket will be flagged as critical.The same %-expandos used for notation data are available here as well.


                            gpg --sig-keyserver-url ...

--set-filename

Use string as the filename which is stored inside messages. This overrides the default, which is to use the actual filenameof the file being encrypted. Using the empty string for string effectively removes the filename from the output.


                            gpg --set-filename ...

--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 isgiven, and PGP to use a "secure viewer" with a claimed Tempest-resistant font to display the message. This option overrides


                            gpg --no-for-your-eyes-only ...

--set-filename.

--no-for-your-eyes-only disables this option.


                            gpg --set-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 enables overwriting files.Defaults to no.


                            gpg --no-use-embedded-filename ...

--cipher-algo

Use name as cipher algorithm. Running the program with the command --version yields a list of supported algorithms. If this isnot used the cipher algorithm is selected from the preferences stored with the key. In general, you do not want to use thisoption as it allows you to violate the OpenPGP standard. --personal-cipher-preferences is the safe way to accomplish the samething.


                            gpg --cipher-algo ...

--digest-algo

Use name as the message digest algorithm. Running the program with the command --version yields a list of supported algo‐rithms. 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.


                            gpg --digest-algo ...

--compress-algo

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 morememory used during 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 supports. If all elsefails, ZIP is used for maximum compatibility.ZLIB may give better compression results than ZIP, as the compression window size is not limited to 8k. BZIP2 may give evenbetter compression results than that, but will use a significantly larger amount of memory while compressing and decompress‐ing. 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 message unreadable with PGP. In general, you do not want to usethis option as it allows you to violate the OpenPGP standard. --personal-compress-preferences is the safe way to accomplishthe same thing.


                            gpg --compress-algo ...

--cert-digest-algo

Use name as the message digest algorithm used when signing a key. Running the program with the command --version yields a listof supported algorithms. Be aware that if you choose an algorithm that GnuPG supports but other OpenPGP implementations donot, then some users will not be able to use the key signatures you make, or quite possibly your entire key.


                            gpg --cert-digest-algo ...

--disable-cipher-algo

Never allow the use of name as cipher algorithm. The given name will not be checked so that a later loaded algorithm willstill get disabled.


                            gpg --disable-cipher-algo ...

--disable-pubkey-algo

Never allow the use of name as public key algorithm. The given name will not be checked so that a later loaded algorithm willstill get disabled.


                            gpg --disable-pubkey-algo ...

--no-throw-keyids

Do not put the recipient key IDs into encrypted messages. This helps to hide the receivers of the message and is a limitedcountermeasure against traffic analysis. ([Using a little social engineering anyone who is able to decrypt the message cancheck whether one of the other recipients is the one he suspects.]) On the receiving side, it may slow down the decryptionprocess because all available secret keys must be tried. --no-throw-keyids disables this option. This option is essentiallythe same as using --hidden-recipient for all recipients.


                            gpg --no-throw-keyids ...

--not-dash-escaped

This option changes the behavior of cleartext signatures so that they can be used for patch files. You should not send such anarmored file via email because all spaces and line endings are hashed too. You can not use this option for data which has 5dashes at the beginning of a line, patch files don't have this. A special armor header line tells GnuPG about this cleartextsignature option.


                            gpg --not-dash-escaped ...

--no-escape-from-lines

Because some mailers change lines starting with "From " to ">From " it is good to handle such lines in a special way when cre‐ating cleartext signatures to prevent the mail system from breaking the signature. Note that all other PGP versions do it thisway too. Enabled by default. --no-escape-from-lines disables this option.


                            gpg --no-escape-from-lines ...

--passphrase-repeat

Specify how many times gpg will request a new passphrase be repeated. This is useful for helping memorize a passphrase.Defaults to 1 repetition.


                            gpg --passphrase-repeat ...

--passphrase-fd

Read the passphrase from file descriptor n. Only the first line will be read from file descriptor n. If you use 0 for n, thepassphrase will be read from STDIN. This can only be used if only one passphrase is supplied.Note that this passphrase is only used if the option --batch has also been given. This is different from GnuPG version 1.x.


                            gpg --passphrase-fd ...

--passphrase-file

Read the passphrase from file file. Only the first line will be read from file file. This can only be used if only onepassphrase is supplied. Obviously, a passphrase stored in a file is of questionable security if other users can read thisfile. Don't use this option if you can avoid it. Note that this passphrase is only used if the option --batch has also beengiven. This is different from GnuPG version 1.x.


                            gpg --passphrase-file ...

--passphrase

Use string as the passphrase. This can only be used if only one passphrase is supplied. Obviously, this is of very question‐able security on a multi-user system. Don't use this option if you can avoid it. Note that this passphrase is only used ifthe option --batch has also been given. This is different from GnuPG version 1.x.


                            gpg --passphrase ...

--pinentry-mode

Set the pinentry mode to mode. Allowed values for mode are:defaultUse the default of the agent, which is ask.ask Force the use of the Pinentry.cancel Emulate use of Pinentry's cancel button.error Return a Pinentry error (``No Pinentry'').loopbackRedirect Pinentry queries to the caller. Note that in contrast to Pinentry the user is not prompted again if he entersa bad password.


                            gpg --pinentry-mode ...

--command-fd

This is a replacement for the deprecated shared-memory IPC mode. If this option is enabled, user input on questions is notexpected from the TTY but from the given file descriptor. It should be used together with --status-fd. See the filedoc/DETAILS in the source distribution for details on how to use it.


                            gpg --command-fd ...

--command-file

Same as --command-fd, except the commands are read out of file file


                            gpg --command-file ...

--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 userID is trivial to forge. --no-allow-non-selfsigned-uid disables.


                            gpg --no-allow-non-selfsigned-uid ...

--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 specialenvironments as it does not ensure the de-facto standard format of user IDs.


                            gpg --allow-freeform-uid ...

--ignore-time-conflict

GnuPG normally checks that the timestamps associated with keys and signatures have plausible values. However, sometimes a sig‐nature 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.


                            gpg --ignore-time-conflict ...

--ignore-valid-from

GnuPG normally does not select and use subkeys created in the future. This option allows the use of such keys and thusexhibits the pre-1.0.7 behaviour. You should not use this option unless there is some clock problem. See also --ignore-time-conflict for timestamp issues with signatures.


                            gpg --ignore-valid-from ...

--ignore-crc-error

The ASCII armor used by OpenPGP is protected by a CRC checksum against transmission errors. Occasionally the CRC gets mangledsomewhere on the transmission channel but the actual content (which is protected by the OpenPGP protocol anyway) is stillokay. This option allows GnuPG to ignore CRC errors.


                            gpg --ignore-crc-error ...

--ignore-mdc-error

This option changes a MDC integrity protection failure into a warning. It is required to decrypt old messages which did notuse an MDC. It may also be useful if a message is partially garbled, but it is necessary to get as much data as possible outof that garbled message. Be aware that a missing or failed MDC can be an indication of an attack. Use with great caution;see also option --rfc2440.


                            gpg --ignore-mdc-error ...

--allow-weak-digest-algos

Signatures made with known-weak digest algorithms are normally rejected with an ``invalid digest algorithm'' message. Thisoption allows the verification of signatures made with such weak algorithms. MD5 is the only digest algorithm considered weakby default. See also --weak-digest to reject other digest algorithms.


                            gpg --allow-weak-digest-algos ...

--weak-digest

Treat the specified digest algorithm as weak. Signatures made over weak digests algorithms are normally rejected. This optioncan be supplied multiple times if multiple algorithms should be considered weak. See also --allow-weak-digest-algos to dis‐able rejection of weak digests. MD5 is always considered weak, and does not need to be listed explicitly.


                            gpg --weak-digest ...

--no-default-keyring

Do not add the default keyrings to the list of keyrings. Note that GnuPG will not operate without any keyrings, so if you usethis option and do not provide alternate keyrings via --keyring or --secret-keyring, then GnuPG will still use the defaultpublic or secret keyrings.


                            gpg --no-default-keyring ...

--no-keyring

Do not add use any keyrings even if specified as options.


                            gpg --no-keyring ...

--skip-verify

Skip the signature verification step. This may be used to make the decryption faster if the signature verification is notneeded.


                            gpg --skip-verify ...

--with-key-data

Print key listings delimited by colons (like --with-colons) and print the public key data.


                            gpg --with-key-data ...

--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. Note that in contrast to --check-signatures the key signatures are not verified.


                            gpg --list-sigs ...

--fast-list-mode

Changes the output of the list commands to work faster; this is achieved by leaving some parts empty. Some applications don'tneed the user ID and the trust information given in the listings. By using this options they can get a faster listing. Theexact behaviour of this option may change in future versions. If you are missing some information, don't use this option.


                            gpg --fast-list-mode ...

--no-literal

This is not for normal use. Use the source to see for what it might be useful.


                            gpg --no-literal ...

--set-filesize

This is not for normal use. Use the source to see for what it might be useful.


                            gpg --set-filesize ...

--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 toreveal the content of one specific message without compromising all messages ever encrypted for one secret key.You can also use this option if you receive an encrypted message which is abusive or offensive, to prove to the administratorsof the messaging system that the ciphertext transmitted corresponds to an inappropriate plaintext so they can take actionagainst the offending user.


                            gpg --show-session-key ...

--override-session-key-fd

Don't use the public key but the session key string respective the session key taken from the first line read from filedescriptor fd. The format of this string is the same as the one printed by --show-session-key. This option is normally notused but comes handy in case someone forces you to reveal the content of an encrypted message; using this option you can dothis without handing out the secret key. Note that using --override-session-key may reveal the session key to all local usersvia the global process table.


                            gpg --override-session-key-fd ...

--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


                            gpg --no-ask-sig-expire ...

--default-sig-expire

is used. --no-ask-sig-expire disables this option.


                            gpg --default-sig-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


                            gpg --no-ask-cert-expire ...

--default-cert-expire

is used. --no-ask-cert-expire disables this option.


                            gpg --default-cert-expire ...

--default-new-key-algo

This option can be used to change the default algorithms for key generation. Note that the advanced key generation commandscan always be used to specify a key algorithm directly. Please consult the source code to learn the syntax of string.


                            gpg --default-new-key-algo ...

--allow-secret-key-import

This is an obsolete option and is not used anywhere.


                            gpg --allow-secret-key-import ...

--no-allow-multiple-messages

Allow processing of multiple OpenPGP messages contained in a single file or stream. Some programs that call GPG are not pre‐pared to deal with multiple messages being processed together, so this option defaults to no. Note that versions of GPG priorto 1.4.7 always allowed multiple messages.Warning: Do not use this option unless you need it as a temporary workaround!


                            gpg --no-allow-multiple-messages ...

--enable-special-filenames

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


                            gpg --enable-special-filenames ...

--no-expensive-trust-checks

Experimental use only.


                            gpg --no-expensive-trust-checks ...

--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 whatyou are doing.


                            gpg --preserve-permissions ...

--default-preference-list

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.


                            gpg --default-preference-list ...

--default-keyserver-url

Set the default keyserver URL to name. This keyserver will be used as the keyserver URL when writing a new self-signature on akey, which includes key generation and changing preferences.


                            gpg --default-keyserver-url ...

--list-config

Display various internal configuration parameters of GnuPG. This option is intended for external programs that call GnuPG toperform tasks, and is thus not generally useful. See the file ‘doc/DETAILS’ in the source distribution for the details ofwhich configuration items may be listed. --list-config is only usable with --with-colons set.


                            gpg --list-config ...

--list-gcrypt-config

Display various internal configuration parameters of Libgcrypt.


                            gpg --list-gcrypt-config ...

--gpgconf-list

This command is similar to --list-config but in general only internally used by the gpgconf tool.


                            gpg --gpgconf-list ...

--gpgconf-test

This is more or less dummy action. However it parses the configuration file and returns with failure if the configurationfile would prevent gpg from startup. Thus it may be used to run a syntax check on the configuration file.Deprecated options


                            gpg --gpgconf-test ...

--no-show-photos

Causes --list-keys, --list-signatures, --list-public-keys, --list-secret-keys, and verifying a signature to also display thephoto ID attached to the key, if any. See also --photo-viewer. These options are deprecated. Use --list-options [no-]show-pho‐tos and/or --verify-options [no-]show-photos instead.


                            gpg --no-show-photos ...

--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.


                            gpg --show-keyring ...

--always-trust

Identical to --trust-model always. This option is deprecated.


                            gpg --always-trust ...

--no-show-notation

Show signature notations in the --list-signatures or --check-signatures listings as well as when verifying a signature with anotation in it. These options are deprecated. Use --list-options [no-]show-notation and/or --verify-options [no-]show-notationinstead.


                            gpg --no-show-notation ...

--no-show-policy-url

Show policy URLs in the --list-signatures or --check-signatures listings as well as when verifying a signature with a policyURL in it. These options are deprecated. Use --list-options [no-]show-policy-url and/or --verify-options [no-]show-policy-urlinstead.EXAMPLESgpg -se -r Bob filesign and encrypt for user Bobgpg --clear-sign filemake a cleartext signaturegpg -sb filemake a detached signaturegpg -u 0x12345678 -sb filemake a detached signature with the key 0x12345678gpg --list-keys user_IDshow keysgpg --fingerprint user_IDshow fingerprintgpg --verify pgpfilegpg --verify sigfile [datafile]Verify the signature of the file but do not output the data unless requested. The second form is used for detached signa‐tures, where sigfile is the detached signature (either ASCII armored or binary) and datafile are the signed data; if this isnot given, the name of the file holding the signed data is constructed by cutting off the extension (".asc" or ".sig") of sig‐file or by asking the user for the filename. If the option --output is also used the signed data is written to the file spec‐ified by that option; use - to write the signed data to stdout.HOW TO SPECIFY A USER IDThere 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 isthe 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 thelow 64 bits of its SHA-1 fingerprint. The use of key Ids is just a shortcut, for all automated processing the fingerprintshould be used.When using gpg an exclamation mark (!) may be appended to force using the specified primary or secondary key and not to tryand calculate which primary or secondary key to use.The last four lines of the example give the key ID in their long form as internally used by the OpenPGP protocol. You can seethe long key ID using the option --with-colons.234567C40F34E556E01347A56A0xAB123456234AABBCC34567C40F323456784E56EAB01AB3FED1347A56120x234AABBCC34567C4By fingerprint.This format is deduced from the length of the string and its content or the 0x prefix. Note, that only the 20 byte versionfingerprint 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 tryand 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 duplicatedkey IDs.1234343434343434C434343434343434123434343434343C3434343434343734349A34340E12343434343434343434EAB34843434343434340xE12343434343434343434EAB3484343434343434gpgsm also accepts colons between each pair of hexadecimal digits because this is the de-facto standard on how to present X.509 fin‐gerprints. gpg also allows the use of the space separated SHA-1 fingerprint as printed by the key listing commands.By exact match on OpenPGP user ID.This is denoted by a leading equal sign. It does not make sense for X.509 certificates.=Heinrich Heine <heinrichh@uni-duesseldorf.de>By exact match on an email address.This is indicated by enclosing the email address in the usual way with left and right angles.<heinrichh@uni-duesseldorf.de>By partial match on an email address.This is indicated by prefixing the search string with an @. This uses a substring search but considers only the mail address(i.e. inside the angle brackets).@heinrichhBy exact match on the subject's DN.This is indicated by a leading slash, directly followed by the RFC-2253 encoded DN of the subject. Note that you can't usethe string printed by gpgsm --list-keys because that one has 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=FRBy exact match on the issuer's DN.This is indicated by a leading hash mark, directly followed by a slash and then directly followed by the RFC-2253 encoded DNof the issuer. This should return the Root cert of the issuer. See note above.#/CN=Root Cert,O=Poets,L=Paris,C=FRBy exact match on serial number and issuer's DN.This is indicated by a hash mark, followed by the hexadecimal representation of the serial number, then followed by a slashand the RFC-2253 encoded DN of the issuer. See note above.#4F03/CN=Root Cert,O=Poets,L=Paris,C=FRBy keygrip.This is indicated by an ampersand followed by the 40 hex digits of a keygrip. gpgsm prints the keygrip when using the command


                            gpg --no-show-policy-url ...

--dump-cert.

&D75F22C3F86E355877348498CDC92BD21010A480By substring match.This is the default mode but applications may want to explicitly indicate this by putting the asterisk in front. Match is notcase sensitive.Heine*Heine. and + prefixesThese prefixes are reserved for looking up mails anchored at the end and for a word search mode. They are not yet implementedand using them is undefined.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, howeverwe don't have to do this because our key database stores this encoding as meta data.FILTER EXPRESSIONSThe options --import-filter and --export-filter use expressions with this syntax (square brackets indicate an optional part and curlybraces a repetition, white space between the elements are allowed):[lc] {[{flag}] PROPNAME op VALUE [lc]}The name of a property (PROPNAME) may only consist of letters, digits and underscores. The description for the filter type describeswhich properties are defined. If an undefined property is used it evaluates to the empty string. Unless otherwise noted, the VALUEmust always be given and may not be the empty string. No quoting is defined for the value, thus the value may not contain thestrings && or ||, which are used as logical connection operators. The flag -- can be used to remove this restriction.Numerical values are computed as long int; standard C notation applies. lc is the logical connection operator; either && for a con‐junction or || for a disjunction. A conjunction is assumed at the begin of an expression. Conjunctions have higher precedence thandisjunctions. If VALUE starts with one of the characters used in any op a space after the op is required.The supported operators (op) are:=~ Substring must match.!~ Substring must not match.= The full string must match.<> The full string must not match.== The numerical value must match.!= The numerical value must not match.<= The numerical value of the field must be LE than the value.< The numerical value of the field must be LT than the value.> The numerical value of the field must be GT than the value.>= The numerical value of the field must be GE than the value.


                            gpg --dump-cert. ...

-le

The string value of the field must be less or equal than the value.


                            gpg -le ...

-lt

The string value of the field must be less than the value.


                            gpg -lt ...

-gt

The string value of the field must be greater than the value.


                            gpg -gt ...

-ge

The string value of the field must be greater or equal than the value.


                            gpg -ge ...

-n

True if value is not empty (no value allowed).


                            gpg -n ...

-z

True if value is empty (no value allowed).


                            gpg -z ...

-t

Alias for "PROPNAME != 0" (no value allowed).


                            gpg -t ...

-f

Values for flag must be space separated. The supported flags are:


                            gpg -f ...

VALUE spans to the end of the expression.


                            gpg -- ...

-c

The filter options concatenate several specifications for a filter of the same type. For example the four options in this example:


                            gpg -c ...

--import-option

keep-uid="uid =~ Alfa"


                            gpg --import-option ...

--export-ownertrust]).

~/.gnupg/trustdb.gpg.lockThe lock file for the trust database.~/.gnupg/random_seedA file used to preserve the state of the internal random pool.~/.gnupg/openpgp-revocs.d/This is the directory where gpg stores pre-generated revocation certificates. The file name corresponds to the OpenPGP fin‐gerprint of the respective key. It is suggested to backup those certificates and if the primary private key is not stored onthe disk to move them to an external storage device. Anyone who can access theses files is able to revoke the correspondingkey. You may want to print them out. You should backup all files in this directory and take care to keep this backup closedaway.Operation is further controlled by a few environment variables:HOME Used to locate the default home directory.GNUPGHOMEIf set directory used instead of "~/.gnupg".GPG_AGENT_INFOThis variable is obsolete; it was used by GnuPG versions before 2.1.PINENTRY_USER_DATAThis value is passed via gpg-agent to pinentry. It is useful to convey extra information to a custom pinentry.COLUMNSLINES Used to size some displays to the full size of the screen.LANGUAGEApart from its use by GNU, it is used in the W32 version to override the language selection done through the Registry. Ifused and set to a valid and available language name (langid), the file with the translation is loaded fromgpgdir/gnupg.nls/langid.mo. Here gpgdir is the directory out of which the gpg binary has been loaded. If it can't be loadedthe Registry is tried and as last resort the native Windows locale system is used.BUGSOn older systems this program should be installed as setuid(root). This is necessary to lock memory pages. Locking memory pages pre‐vents the operating system from writing memory pages (which may contain passphrases or other sensitive material) to disk. If you getno warning message about insecure memory your operating system supports locking without being root. The program drops root privilegesas 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'' or ``hiber‐nate''). This writes all memory to disk before going into a low power or even powered off mode. Unless measures are taken in theoperating system to protect the saved memory, passphrases or other sensitive material may be recoverable from it later.Before you report a bug you should first search the mailing list archives for similar problems and second check whether such a bughas already been reported to our bug tracker at https://bugs.gnupg.org.


                            gpg --export-ownertrust]). ...