Commands not specific to the function¶

--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 command-line options. Note that you cannot arbitrarily abbreviate this command (though you can use its short form -h).

--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 operation¶

--sign

-s

Sign a message. This command may be combined with --encrypt (to sign and encrypt a message), --symmetric (to sign and symmetrically encrypt a message), or both --encrypt and --symmetric (to sign and encrypt a message that can be decrypted using a secret key or a passphrase). The signing key is chosen by default or can be set explicitly using the --local-user and --default-key options.

--clear-sign

--clearsign

Make a cleartext signature. The content in a cleartext signature is readable without any special software. OpenPGP software is only needed to verify the signature. cleartext signatures may modify end-of-line whitespace for platform independence and are not intended to be reversible. The signing key is chosen by default or can be set explicitly using the --local-user and --default-key options.

--detach-sign

-b

Make a detached signature.

--encrypt

-e

Encrypt data to one or more public keys. This command may be combined with --sign (to sign and encrypt a message), --symmetric (to encrypt a message that can be decrypted using a secret key or a passphrase), or --sign and --symmetric together (for a signed message that can be decrypted using a secret key or a passphrase). --recipient and related options specify which public keys to use for encryption.

--symmetric

-c

Encrypt with a symmetric cipher using a passphrase. The default symmetric cipher used is AES-128, but may be chosen with the --cipher-algo option. This command 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). gpg caches the passphrase used for symmetric encryption so that a decrypt operation may not require that the user needs to enter the passphrase. The option --no-symkey-cache can be used to disable this feature.

--store

Store only (make a simple 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 that don't begin with an encrypted message.

--verify

Assume that the first argument is a signed file and verify it without generating any output. With no arguments, the signature packet is read from STDIN. If only one argument is given, the specified file is expected to include a complete signature.

With more than one argument, the first argument should specify a file with a detached signature and the remaining files should contain the signed data. To read the signed data from STDIN, use ‘-’ as the second filename. For security reasons, a detached signature will not read the signed material from STDIN if not explicitly specified.

Note: If the option --batch is not used, gpg may assume that a single argument is a file with a detached signature, and it will try to find a matching data file by stripping certain suffixes. Using this historical feature to verify a detached signature is strongly discouraged; you should always specify the data file explicitly.

Note: When verifying a cleartext signature, gpg verifies only what makes up the cleartext signed data and not any extra data outside of the cleartext signature or the header lines directly following the dash marker line. The option --output may be used to write out the actual signed data, but there are other pitfalls with this format as well. It is suggested to avoid cleartext signatures in favor of detached signatures.

Note: Sometimes the use of the gpgv tool is easier than using the full-fledged gpg with this option. gpgv is designed to compare signed data against a list of trusted keys and returns with success only for a good signature. It has its own manual page.

--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 the specified keys. If no keys are specified, then all keys from the configured public keyrings are listed.

Never use the output of this command in scripts or other programs. The output is intended only for humans and its format is likely to change. The --with-colons option emits the output in a stable, machine-parseable format, which is intended for use by scripts and other programs.

--list-secret-keys

-K

List the specified secret keys. If no keys are specified, then all known secret keys are listed. A # after the initial tags sec or ssb means that the secret key or subkey is currently not usable. We also say that this key has been taken offline (for example, a primary key can be taken offline by exporting the key using the command --export-secret-subkeys). A > after these tags indicate that the key is stored on a smartcard. See also --list-keys.

--check-signatures

--check-sigs

Same as --list-keys, but the key signatures are verified and listed too. 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 below. A "!" indicates that the signature has been successfully verified, a "-" denotes a bad signature and a "%" is used if an error occurred while checking the signature (e.g. a non supported algorithm). Signatures where the public key is not available are not listed; to see their keyids the command --list-sigs can be used.

For each signature listed, there are several flags in between the signature status flag and keyid. These flags give additional information about each key 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 nonRevocable 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").

--locate-keys

--locate-external-keys

Locate the keys given as arguments. This command basically uses the same algorithm as used when locating keys for encryption and may thus be used to see what keys gpg might use. In particular external methods as defined by --auto-key-locate are used to locate a key if the arguments comain valid mail addresses. Only public keys are listed.

The variant --locate-external-keys does not consider a locally existing key and can thus be used to force the refresh of a key via the defined external methods. If a fingerprint is given and and the methods defined by --auto-key-locate define LDAP servers, the key is fetched from these resources; defined non-LDAP keyservers are skipped.

--show-keys

This commands takes OpenPGP keys as input and prints information about them in the same way the command --list-keys does for locally stored key. In addition the list options show-unusable-uids, show-unusable-subkeys, show-notations and show-policy-urls are also enabled. As usual for automated processing, this command should be combined with the option --with-colons.

--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 --check-signatures. If this command is given twice, the fingerprints of all secondary keys are listed too. This command also forces pretty printing of fingerprints if the keyid format has been set to "none".

--list-packets

List only the sequence of packets. This command is only useful for debugging. When used with option --verbose the actual MPI values are dumped and not only their lengths. Note that the output of this command may change with new releases.

--edit-card

--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 https://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 --edit-card command.

--delete-keys 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. If the exclamation mark syntax is used with the fingerprint of a subkey only that subkey is deleted; if the exclamation mark is used with the fingerprint of the primary key the entire public key is deleted.

--delete-secret-keys name

Remove key from the secret keyring. In batch mode the key must be specified by fingerprint. The option --yes can be used to advise gpg-agent not to request a confirmation. This extra pre-caution is done because gpg can't be sure that the secret key (as controlled by gpg-agent) is only used for the given OpenPGP public key. If the exclamation mark syntax is used with the fingerprint of a subkey only the secret part of that subkey is deleted; if the exclamation mark is used with the fingerprint of the primary key only the secret part of the primary key is deleted.

--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. The option --yes can be used to advise gpg-agent not to request a confirmation.

--export

Either export all keys from all keyrings (default keyring and those registered via option --keyring), or if at least one name is given, those of the given name. The exported keys are written to STDOUT or to the file given with option --output. Use together with --armor to mail those keys.

--send-keys keyIDs

Similar to --export but sends the keys to a keyserver. Fingerprints may be used instead of key IDs. Don't send your complete keyring to a keyserver --- select only those keys which are new or changed by you. If no keyIDs are given, gpg does nothing.

Take care: Keyservers are by design write only systems and thus it is not possible to ever delete keys once they have been send to a keyserver.

--export-secret-keys

--export-secret-subkeys

Same as --export, but exports the secret keys instead. The exported keys are written to STDOUT or to the file given with option --output. This command is often used along with the option --armor to allow for easy printing of the key for paper backup; however the external tool paperkey does a better job of creating backups on paper. Note that exporting a secret key can be a security risk if the exported keys are sent over an insecure channel.

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 implementations can not be expected to successfully import such a key. Its intended use is in generating a full key with an additional signing subkey on a dedicated machine. This command then exports the key without the primary key to the main machine.

GnuPG may ask you to enter the passphrase for the key. This is required, because the internal protection method of the secret key is different from the one specified by the OpenPGP protocol.

--export-ssh-key

This command is used to export a key in the OpenSSH public key format. It requires the specification of one key by the usual means and exports the latest valid subkey which has an authentication capability to STDOUT or to the file given with option --output. That output can directly be added to ssh's ‘authorized_key’ file.

By specifying the key to export using a key ID or a fingerprint suffixed with an exclamation mark (!), a specific subkey or the primary key can be exported. This does not even require that the key has the authentication capability flag set.

--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.

--receive-keys keyIDs

--recv-keys keyIDs

Import the keys with the given keyIDs from a 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. Calling this with no arguments will refresh the entire keyring.

--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. Note that keyservers search for names in a different and simpler way than gpg does. The best choice is to use a mail address. Due to data privacy reasons keyservers may even not even allow searching by user id or mail address and thus may only return results when being used with the --recv-key command to search by key fingerprint or keyid.

--fetch-keys URIs

Retrieve keys located at the specified URIs. Note that different installations of GnuPG may support different protocols (HTTP, FTP, LDAP, etc.). When using HTTPS the system provided root certificates are used by this command.

--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 which can't be re-created from a corrupted trustdb. Example:

  gpg --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


  gpg --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 keyring. 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 "*" for algo) digests for all available algorithms are printed.

--gen-random 0|1|2 count

Emit count random bytes of the given quality level 0, 1 or 2. If count is not given or zero, an endless sequence of random bytes will be emitted. If used with --armor the output will be base64 encoded. PLEASE, don't use this command 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 subject to change with ant release.

--enarmor

--dearmor

Pack or unpack an arbitrary input into/from an OpenPGP ASCII armor. This is a GnuPG extension to OpenPGP and in general not very useful.

--tofu-policy {auto|good|unknown|bad|ask} keys

Set the TOFU policy for all the bindings associated with the specified keys. For more information about the meaning of the policies, see: [trust-model-tofu]. The keys may be specified either by their fingerprint (preferred) or their keyid.

How to manage your keys¶

This section explains the main commands for key management.

--quick-generate-key user-id [algo [usage [expire]]]

--quick-gen-key

This is a simple command to generate a standard key with one user id. In contrast to --generate-key the key is generated directly without the need to answer a bunch of prompts. Unless the option --yes is given, the key creation will be canceled if the given user id already exists in the keyring.

If invoked directly on the console without any special options an answer to a ``Continue?'' style confirmation prompt is required. In case the user id already exists in the keyring a second prompt to force the creation of the key will show up.

If algo or usage are given, only the primary key is created and no prompts are shown. To specify an expiration date but still create a primary and subkey use ``default'' or ``future-default'' for algo and ``default'' for usage. For a description of these optional arguments see the command --quick-add-key. The usage accepts also the value ``cert'' which can be used to create a certification only primary key; the default is to a create certification and signing key.

The expire argument can be used to specify an expiration date for the key. Several formats are supported; commonly the ISO formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To make the key expire in N seconds, N days, N weeks, N months, or N years use ``seconds=N'', ``Nd'', ``Nw'', ``Nm'', or ``Ny'' respectively. Not specifying a value, or using ``-'' results in a key expiring in a reasonable default interval. The values ``never'', ``none'' can be used for no expiration date.

If this command is used with --batch, --pinentry-mode has been set to loopback, and one of the passphrase options (--passphrase, --passphrase-fd, or --passphrase-file) is used, the supplied passphrase is used for the new key and the agent does not ask for it. To create a key without any protection --passphrase '' may be used.

To create an OpenPGP key from the keys available on the currently inserted smartcard, the special string ``card'' can be used for algo. If the card features an encryption and a signing key, gpg will figure them out and creates an OpenPGP key consisting of the usual primary key and one subkey. This works only with certain smartcards. Note that the interactive --full-gen-key command allows to do the same but with greater flexibility in the selection of the smartcard keys.

Note that it is possible to create a primary key and a subkey using non-default algorithms by using ``default'' and changing the default parameters using the option --default-new-key-algo.

--quick-set-expire fpr expire [*|subfprs]

With two arguments given, directly set the expiration time of the primary key identified by fpr to expire. To remove the expiration time 0 can be used. With three arguments and the third given as an asterisk, the expiration time of all non-revoked and not yet expired subkeys are set to expire. With more than two arguments and a list of fingerprints given for subfprs, all non-revoked subkeys matching these fingerprints are set to expire.

--quick-add-key fpr [algo [usage [expire]]]

Directly add a subkey to the key identified by the fingerprint fpr. Without the optional arguments an encryption subkey is added. If any of the arguments are given a more specific subkey is added.

algo may be any of the supported algorithms or curve names given in the format as used by key listings. To use the default algorithm the string ``default'' or ``-'' can be used. Supported algorithms are ``rsa'', ``dsa'', ``elg'', ``ed25519'', ``cv25519'', and other ECC curves. For example the string ``rsa'' adds an RSA key with the default key length; a string ``rsa4096'' requests that the key length is 4096 bits. The string ``future-default'' is an alias for the algorithm which will likely be used as default algorithm in future versions of gpg. To list the supported ECC curves the command gpg --with-colons --list-config curve can be used.

Depending on the given algo the subkey may either be an encryption subkey or a signing subkey. If an algorithm is capable of signing and encryption and such a subkey is desired, a usage string must be given. This string is either ``default'' or ``-'' to keep the default or a comma delimited list (or space delimited list) of keywords: ``sign'' for a signing subkey, ``auth'' for an authentication subkey, and ``encr'' for an encryption subkey (``encrypt'' can be used as alias for ``encr''). The valid combinations depend on the algorithm.

The expire argument can be used to specify an expiration date for the key. Several formats are supported; commonly the ISO formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To make the key expire in N seconds, N days, N weeks, N months, or N years use ``seconds=N'', ``Nd'', ``Nw'', ``Nm'', or ``Ny'' respectively. Not specifying a value, or using ``-'' results in a key expiring in a reasonable default interval. The values ``never'', ``none'' can be used for no expiration date.

--generate-key

--gen-key

Generate a new key pair using the current default parameters. This is the standard command to create a new key. In addition to the key a revocation certificate is created and stored in the ‘openpgp-revocs.d’ directory below the GnuPG home directory.

--full-generate-key

--full-gen-key

Generate a new key pair with dialogs for all options. This is an extended version of --generate-key.

There is also a feature which allows you to create keys in batch mode. See the manual section ``Unattended key generation'' on how to use this.

--generate-revocation name

--gen-revoke name

Generate a revocation certificate for the complete key. To only revoke a subkey or a key signature, use the --edit command.

This command merely creates the revocation certificate so that it can be used to revoke the key if that is ever needed. To actually revoke a key the created revocation certificate needs to be merged with the key to revoke. This is done by importing the revocation certificate using the --import command. Then the revoked key needs to be published, which is best done by sending the key to a keyserver (command --send-key) and by exporting (--export) it to a file which is then send to frequent communication partners.

--generate-designated-revocation name

--desig-revoke name

Generate a designated revocation certificate for a key. This allows a user (with the permission of the keyholder) 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.

If the option --only-sign-text-ids is specified, then any non-text based user ids (e.g., photo IDs) will not be selected for signing.

--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 subcommand "lsign" from --edit-key.

--quick-sign-key fpr [names]

--quick-lsign-key fpr [names]

Directly sign a key from the passphrase without any further user interaction. The fpr must be the verified primary fingerprint of a key in the local keyring. If no names are given, all useful user ids are signed; with given [names] only useful user ids matching one of theses names are signed. By default, or if a name is prefixed with a '*', a case insensitive substring match is used. If a name is prefixed with a '=' a case sensitive exact match is done.

The command --quick-lsign-key marks the signatures as non-exportable. If such a non-exportable signature already exists the --quick-sign-key turns it into a exportable signature. If you need to update an existing signature, for example to add or change notation data, you need to use the option --force-sign-key.

This command uses reasonable defaults and thus does not provide the full flexibility of the "sign" subcommand from --edit-key. Its intended use is to help unattended key signing by utilizing a list of verified fingerprints.

--quick-add-uid user-id new-user-id

This command adds a new user id to an existing key. In contrast to the interactive sub-command adduid of --edit-key the new-user-id is added verbatim with only leading and trailing white space removed, it is expected to be UTF-8 encoded, and no checks on its form are applied.

--quick-revoke-uid user-id user-id-to-revoke

This command revokes a user ID on an existing key. It cannot be used to revoke the last user ID on key (some non-revoked user ID must remain), with revocation reason ``User ID is no longer valid''. If you want to specify a different revocation reason, or to supply supplementary revocation text, you should use the interactive sub-command revuid of --edit-key.

--quick-revoke-sig fpr signing-fpr [names]

This command revokes the key signatures made by signing-fpr from the key specified by the fingerprint fpr. With names given only the signatures on user ids of the key matching any of the given names are affected (see --quick-sign-key). If a revocation already exists a notice is printed instead of creating a new revocation; no error is returned in this case. Note that key signature revocations may be superseded by a newer key signature and in turn again revoked.

--quick-set-primary-uid user-id primary-user-id

This command sets or updates the primary user ID flag on an existing key. user-id specifies the key and primary-user-id the user ID which shall be flagged as the primary user ID. The primary user ID flag is removed from all other user ids and the timestamp of all affected self-signatures is set one second ahead.

--change-passphrase user-id

--passwd user-id

Change the passphrase of the secret key belonging to the certificate specified as user-id. This is a shortcut for the sub-command passwd of the edit key menu. When using together with the option --dry-run this will not actually change the passphrase but check that the current passphrase is correct.

How to change the configuration¶

These options are used to change the configuration and most of them 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. This option may be given multiple times. In this case, the last 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.

--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 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. Should not be used in an option file.

-v, --verbose

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

--no-verbose

Reset verbose level to 0. Should not be used in an option file.

-q, --quiet

Try to be as quiet as possible. Should not be used in an option file.

--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’.

It is highly recommended to use this option along with the options --status-fd and --with-colons for any unattended use of gpg. Should not be used in an option file.

--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. Should not be used in an option file.

--no

Assume "no" on most questions. Should not be used in an option file.

--list-options parameters

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

--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:

--enable-large-rsa

--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 is generally recommended. These large keys don't significantly improve security, but they are more expensive to use, and their signatures and certifications are larger. This option is only available if the binary was build with large-secmem support.

--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 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 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"), "%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 actual percent sign. If neither %i or %I are present, then the photo will be supplied to the viewer on standard input.

On Unix the default viewer is xloadimage -fork -quiet -title 'KeyID 0x%k' STDIN with a fallback to display -title 'KeyID 0x%k' %i and finally to xdg-open %i. On Windows !ShellExecute 400 %i is used; here the command is a meta command to use that API call followed by a wait time in milliseconds which is used to give the viewer time to read the temporary image file before gpg deletes it again. Note that if your image viewer program is not secure, then executing it from gpg does not make it secure.

--exec-path string

Sets a list of directories to search for photo viewers If not provided photo viewers use the PATH environment variable.

--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" unless --homedir or $GNUPGHOME is 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.

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

--primary-keyring file

This is a varian of --keyring and designates file as the primary public keyring. This means that newly imported keys (via --import or keyserver --recv-from) will go to this keyring.

--secret-keyring file

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

--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 command line. It also overrides any home directory stated through the environment variable ‘GNUPGHOME’ or (on Windows systems) by means of the Registry entry HKCU\Software\GNU\GnuPG:HomeDir.

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

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

--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. This option should not be used on Windows. Valid values for name are:

--utf8-strings

--no-utf8-strings

Assume that command line arguments are given as UTF-8 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 multiple times. This option should not be used in an option file.

This option has no effect on Windows. There the internal used UTF-8 encoding is translated for console input and output. The command line arguments are expected as Unicode and translated to UTF-8. Thus when calling this program from another, make sure to use the Unicode version of CreateProcess.

--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 platforms.

--ask-cert-level

--no-ask-cert-level

When making a key signature, prompt for a certification level. If this option is not specified, the certification 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 disables 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 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 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.

--trusted-key long key ID or fingerprint

Assume that the specified key (which should be given as fingerprint) 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. If the given key is not locally available but an LDAP keyserver is configured the missing key is imported from that server.

--trust-model {pgp|classic|tofu|tofu+pgp|direct|always|auto}

Set what trust model GnuPG should follow. The models are:

--auto-key-locate mechanisms

--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), and there are no "user@example.com" keys on the local keyring. This option takes any number of the mechanisms listed below, in the order they are to be tried. Instead of listing the mechanisms as comma delimited arguments, the option may also be given several times to add more mechanism. The option --no-auto-key-locate or the mechanism "clear" resets the list. The default is "local,wkd".

--auto-key-import

--no-auto-key-import

This is an offline mechanism to get a missing key for signature verification and for later encryption to this key. If this option is enabled and a signature includes an embedded key, that key is used to verify the signature and on verification success that key is imported. The default is --no-auto-key-import.

On the sender (signing) site the option --include-key-block needs to be used to put the public part of the signing key as “Key Block subpacket” into the signature.

--auto-key-retrieve

--no-auto-key-retrieve

These options enable or disable the automatic retrieving of keys from a keyserver when verifying signatures made by keys that are not on the local keyring. The default is --no-auto-key-retrieve.

The order of methods tried to lookup the key is:

1. If the option --auto-key-import is set and the signatures includes an embedded key, that key is used to verify the signature and on verification success that key is imported.

2. If a preferred keyserver is specified in the signature and the option honor-keyserver-url is active (which is not the default), that keyserver is tried. Note that the creator of the signature uses the option --sig-keyserver-url to specify the preferred keyserver for data signatures.

3. If the signature has the Signer's UID set (e.g. using --sender while creating the signature) a Web Key Directory (WKD) lookup is done. This is the default configuration but can be disabled by removing WKD from the auto-key-locate list or by using the option --disable-signer-uid.

4. If the option honor-pka-record is active, the legacy PKA method is used.

5. If any keyserver is configured and the Issuer Fingerprint is part of the signature (since GnuPG 2.1.16), the configured keyservers are tried.

Note that this option makes a "web bug" like behavior possible. Keyserver or Web Key Directory operators can see which keys you 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.

--keyid-format {none|short|0xshort|long|0xlong}

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" to either to include an "0x" at the beginning of the key ID, as in 0x99242560. Note that this option is ignored if the option --with-colons is used.

--keyserver name

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 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"/"hkps" for the HTTP (or compatible) keyservers or "ldap"/"ldaps" for the LDAP keyservers. Note that your particular installation of GnuPG may have other keyserver types available as well. Keyserver schemes are case-insensitive.

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=value}

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:

The default list of options is: "self-sigs-only, repair-keys, repair-pks-subkey-bug, export-attributes, honor-pka-record". However, if the actual used source is an LDAP server "no-self-sigs-only" is assumed unless "self-sigs-only" has been explictly configured.

--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)

--tofu-default-policy {auto|good|unknown|bad|ask}

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

--max-cert-depth n

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

--no-sig-cache

Do not cache the verification status of key signatures. Caching gives a much better performance in key listings. However, if you 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 your public keyring.

--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. gpg always requires the agent.

--gpg-agent-info

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

--agent-program file

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

--dirmngr-program file

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

--disable-dirmngr

Entirely disable the use of the 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 mostly useful on machines where the connection to gpg-agent has been redirected to another machines. If dirmngr is required on the remote machine, it may be started manually using gpgconf --launch dirmngr.

--lock-once

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

--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 --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 useful 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 directory (--homedir) permissions. Note that the permission checks that GnuPG performs are not intended to be authoritative, but rather they simply warn about certain 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.

--require-secmem

--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 gpg.

--expert

--no-expert

Allow the user to do certain nonsensical or "silly" things like signing an expired or revoked key, or certain 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 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.

--recipient-file file

-f

This option is similar to --recipient except that it encrypts to a key stored in the given file. file must be the name of a file containing exactly one key. gpg assumes that the key in this file is fully valid.

--hidden-recipient-file file

-F

This option is similar to --hidden-recipient except that it encrypts to a key stored in the given file. file must be the name of a file containing exactly one key. gpg assumes that the key in this file is fully valid.

--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=value}

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 cannot 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.

--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.

--sender mbox

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

--try-secret-key name

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

--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. This option forces the behaviour as used by anonymous recipients (created by using --throw-keyids or --hidden-recipient) and might come handy in case where an encrypted message contains a bogus key ID.

--skip-hidden-recipients

--no-skip-hidden-recipients

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

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. To write to stdout use - as the filename.

--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 significantly larger than the original OpenPGP message. While GnuPG works properly with such messages, there is often a desire to set a maximum file size that will be generated before processing is forced to stop by the OS limits. Defaults to 0, which means "no limit".

--input-size-hint n

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 is only useful if the input is not taken from a file. GPG may use this hint to optimize its buffer allocation strategy. It is also used by the --status-fd line ``PROGRESS'' to provide a value for ``total'' if that is not available by other means.

--key-origin string[,url]

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

--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-filter {name=expr}

--export-filter {name=expr}

These options define an import/export filter which are applied to the imported/exported keyblock right before it will be stored/written. name defines the type of filter to use, expr the expression to evaluate. The option can be used several times which then appends more expression to the same name.

The available filter types are:

For the syntax of the expression see the chapter "FILTER EXPRESSIONS". The property names for the expressions depend on the actual filter type and are indicated in the following table.

The available properties are:

--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:

--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.

--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. --with-colons). Note that the legacy format does not convey suitable information for elliptic curves.

--with-fingerprint

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

--with-subkey-fingerprint

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

--with-icao-spelling

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

--with-keygrip

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

--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 is always printed. This data is currently experimental and shall not be considered part of the stable API.

--with-wkd-hash

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

--with-secret

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

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 recipient 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 communicating between two platforms that have different line ending conventions (UNIX-like to Mac, Mac to Windows, etc). --no-textmode disables this option, and is the default.

--force-v3-sigs

--no-force-v3-sigs

--force-v4-certs

--no-force-v4-certs

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

--force-mdc

--disable-mdc

These options are obsolete and have no effect since GnuPG 2.2.8. The MDC is always used. But note: If the creation of a legacy non-MDC message is exceptionally required, the option --rfc2440 allows for this.

--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 key has been specified with local-user using a mail address, or with sender. This information can be helpful for verifier to locate the key; see option --auto-key-retrieve.

--include-key-block

This option is used to embed the actual signing key into a data signature. The embedded key is stripped down to a single user id and includes only the signing subkey used to create the signature as well as as valid encryption subkeys. All other info is removed from the key to keep it and thus the signature small. This option is the OpenPGP counterpart to the gpgsm option --include-certs.

--personal-cipher-preferences string

Set the list of personal cipher preferences to string. Use gpg --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 recipients. The most highly ranked cipher in this list is also used for the --symmetric encryption command.

--personal-digest-preferences string

Set the list of personal digest preferences to string. Use gpg --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 recipients. The most highly ranked digest algorithm in this list is also used when signing without encryption (e.g. --clear-sign or --sign).

--personal-compress-preferences string

Set the list of personal compression preferences to string. Use gpg --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 recipients. 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 for symmetric encryption with a passphrase if --personal-cipher-preferences and --cipher-algo are not given. The default is AES-128.

--s2k-digest-algo name

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

--s2k-mode n

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

--s2k-count n

Specify how many times the passphrases mangling for symmetric encryption is repeated. This value may range between 1024 and 65011712 inclusive. The default is inquired from gpg-agent. 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 only meaningful if --s2k-mode is set to the default of 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 additional 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.

--rfc4880bis

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

--rfc2440

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

--pgp6

Set up all options to be as PGP 6 compliant as possible. 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 --escape-from-lines.

--pgp7

Set up all options to be as PGP 7 compliant as possible. 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 possible. 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 algorithms are allowed except for the SHA224, SHA384, and SHA512 digests.

--compliance string

This option can be used instead of one of the options above. Valid values for string are the above option names (without the double dash) and possibly others as shown when using "help" for string.

--min-rsa-length n

This option adjusts the compliance mode "de-vs" for stricter key size requirements. For example, a value of 3000 turns rsa2048 and dsa2048 keys into non-VS-NfD compliant keys.

--require-compliance

To check that data has been encrypted according to the rules of the current compliance mode, a gpg user needs to evaluate the status lines. This is allows frontends to handle compliance check in a more flexible way. However, for scripted use the required evaluation of the status-line requires quite some effort; this option can be used instead to make sure that the gpg process exits with a failure if the compliance rules are not fulfilled. Note that this option has currently an effect only in "de-vs" mode.

Doing things one usually doesn't want to do¶

-n

--dry-run

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

--list-only

Changes the behaviour of some commands. This is like --dry-run but different in some cases. The semantic of this option 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-level level

Select the debug level for investigating problems. level may be a numeric value or by a keyword:

How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. They are however carefully selected to best aid in debugging.

--debug flags

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 flag names. To get a list of all supported flags the single word "help" can be used.

--debug-all

Set all useful debugging flags.

--debug-iolbf

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

--faked-system-time epoch

This option is only useful for testing; it sets the system time back or forth to epoch which is the number of seconds elapsed since 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.

--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 performance 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.

--log-file file

--logger-file file

Same as --logger-fd, except the logger data is written to file file. Use ‘socket://’ to log to a socket. Note that in this version of gpg the option has only an effect if --batch is also used.

--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 cleartext 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 comment 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. If given once only the name of the program and the major number is emitted, given twice the minor is also emitted, given thrice the micro is added, and given four times an operating system identification is also emitted. --no-emit-version (default) disables the version line.

--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 appropriate keyname and domain name, of course). 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 set correctly. If you prefix name with an exclamation mark (!), the notation data will be flagged as critical (rfc4880:5.2.3.16). --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 single "%". %k, %K, and %f are only meaningful when making a key signature (certification), and %c is only meaningful when using the OpenPGP smartcard.

--known-notation name

Adds name to a list of known critical signature notations. The effect of this is that gpg will not mark a signature with a critical signature notation of that name as bad. Note that gpg already knows by default about a few critical signatures notation names.

--sig-policy-url string

--cert-policy-url string

--set-policy-url string

Use string as a Policy URL for signatures (rfc4880:5.2.3.20). If you prefix it with an exclamation 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 available here as well.

--sig-keyserver-url string

Use string as a preferred keyserver URL for data signatures. 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 available here as well.

--set-filename string

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

--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 enables overwriting files. Defaults to no. Note that the option --output overrides this option.

--cipher-algo name

Use name as cipher algorithm. Running the program with the command --version yields a list of supported algorithms. 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 accomplish 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 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 else fails, 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 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 message 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 messages. 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.]) 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 signatures 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 cleartext 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 special 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 gpg will request a new passphrase be repeated. This is useful for helping memorize a passphrase. Defaults to 1 repetition; can be set to 0 to disable any passphrase repetition. Note that a n greater than 1 will pop up the pinentry window n+1 times even if a modern pinentry with two entry fields is used.

--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 supplied.

Note that since Version 2.0 this passphrase is only used if the option --batch has also been given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.

--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 since Version 2.0 this passphrase is only used if the option --batch has also been given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.

--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 since Version 2.0 this passphrase is only used if the option --batch has also been given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.

--pinentry-mode mode

Set the pinentry mode to mode. Allowed values for mode are:

--no-symkey-cache

Disable the passphrase cache used for symmetrical en- and decryption. This cache is based on the message specific salt value (cf. --s2k-mode).

--request-origin origin

Tell gpg to assume that the operation ultimately originated at origin. Depending on the origin certain restrictions are applied and the Pinentry may include an extra note on the origin. Supported values for origin are: local which is the default, remote to indicate a remote origin or browser for an operation requested by a web browser.

--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. However, 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.

--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 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. It is required to decrypt old messages which did not use an MDC. It may also be useful if a message is partially garbled, but it is necessary to get as much data as possible out of 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.

--allow-weak-digest-algos

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

--weak-digest name

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

--allow-weak-key-signatures

To avoid a minor risk of collision attacks on third-party key signatures made using SHA-1, those key signatures are considered invalid. This options allows to override this restriction.

--override-compliance-check

The signature verification only allows the use of keys suitable in the current compliance mode. If the compliance mode has been forced by a global option, there might be no way to check certain signature. This option allows to override this and prints an extra warning in such a case. This option is ignored in --batch mode so that no accidental unattended verification may happen.

--no-default-keyring

Do not add the default keyring to the list of keyrings. Note that GnuPG needs for almost all operations a keyring. Thus if you use this option and do not provide alternate keyrings via --keyring, then GnuPG will still use the default keyring.

--no-keyring

Do not use any keyring at all. This overrides the default and all options which specify keyrings.

--skip-verify

Skip the signature verification step. This may be used to make the decryption faster if the signature verification is not needed.

--with-key-data

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

--list-signatures

--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. This command can be used to create a list of signing keys missing in the local keyring; for example:

      gpg --list-sigs --with-colons USERID | \


        awk -F: '$1=="sig" && $2=="?" {if($13){print $13}else{print $5}}'

--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 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.

You can also use this option if you receive an encrypted message which is abusive or offensive, to prove to the administrators of the messaging system that the ciphertext transmitted corresponds to an inappropriate plaintext so they can take action against the offending user.

--override-session-key string

--override-session-key-fd fd

Don't use the public key but the session key string respective the session key taken from the first line read from file descriptor fd. 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. Note that using --override-session-key may reveal the session key to all local users via the global process table. Often it is useful to combine this option with --no-keyring.

--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.

--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".

--default-new-key-algo string

This option can be used to change the default algorithms for key generation. The string is similar to the arguments required for the command --quick-add-key but slightly different. For example the current default of "rsa2048/cert,sign+rsa2048/encr" (or "rsa3072") can be changed to the value of what we currently call future default, which is "ed25519/cert,sign+cv25519/encr". You need to consult the source code to learn the details. Note that the advanced key generation commands can always be used to specify a key algorithm directly.

--force-sign-key

This option modifies the behaviour of the commands --quick-sign-key, --quick-lsign-key, and the "sign" sub-commands of --edit-key by forcing the creation of a key signature, even if one already exists.

--forbid-gen-key

This option is intended for use in the global config file to disallow the use of generate key commands. Those commands will then fail with the error code for Not Enabled.

--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. Future versions of GnUPG will remove this option.

Warning: Do not use this option unless you need it as a temporary workaround!

--enable-special-filenames

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

--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 generally 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.

--list-gcrypt-config

Display various internal configuration parameters of Libgcrypt.

--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 configuration file.

Deprecated options¶

--show-photos

--no-show-photos

Causes --list-keys, --list-signatures, --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-signatures or --check-signatures listings as well as when verifying a signature with a notation in it. These options are deprecated. 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-signatures or --check-signatures 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.