4.2.2 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". It is suggested to use a fingerprint or at least a long keyID for name. 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". It is suggested to use a fingerprint or at least a long keyID for name. 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 containing a proper mail address or just a plain mail address. The option can be given multiple times.

When creating a signature this option tells gpg the signing key’s user id used to make the signature and embeds that user ID into the created signature (using OpenPGP’s “Signer’s User ID” subpacket). If the option is given multiple times a suitable user ID is picked. However, if the signing key was specified directly by using a mail address (i.e. not by using a fingerprint or key ID) this option is used and the mail address is embedded in the created signature.

When verifying a signature mbox is used to restrict the information printed by the TOFU code to matching user IDs. If the option is used and the signature contains a “Signer’s User ID” subpacket that information is is also used to restrict the printed information. Note that GnuPG considers only the mail address part of a User ID.

If this option or the said subpacket is available the TRUST lines as printed by option status-fd correspond to the corresponding User ID; if no User ID is known the TRUST lines are computed directly on the key and do not give any information about the User ID. In the latter case it his highly recommended to scripts and other frontends to evaluate the VALIDSIG line, retrieve the key and print all User IDs along with their validity (trust) information.

--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.