Questions about "--group" for group encryptions.

Zy Zylek zy.zylek at
Sat Feb 20 03:53:11 CET 2010

I'm looking for a way to include a group of people in gpg file
encryption/decryption (not email-based, just gpg encrypted files) without
having to incorporate individual names, yet also such that more people can
be added to the group in the future and that they will be able to access
previously encrypted files because they joined the group after the old files
were encrypted.

Does the "--group" option in gpg serve this purpose?

Or is there another way to go about it?

I checked the man file for gpg, read the bit on --group and similar
group-related information and it has this:

  --group name=value1
Sets up a named group, which is similar to aliases in email pro‐
grams. Any time the group name is a recipient (-r or --recipi‐
ent), it will be expanded to the values specified. Multiple
groups with the same name are automatically merged into a single

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.

Remove all entries from the --group list.
I found on a google search the following information someone provided
regarding adding a line to the gpg.conf file:

*group name_you_want_to_use = keyid1 keyid2 keyid3 keyid4*

That is a little confusing.

Does that mean that people with their own individual keys can be added or
removed from the group?

Does the group have its own key?

If an individual's key is in the group then can they decrypt files that have
been encrypted before they joined the group using the "group key" as

But if their key has been removed from the group then can they still decrypt
previous files that were encrypted using the "group key" as recipient?

If I add people to a group via gpg.conf (using the line in bold type font
above), and if I later want to add only one person to the group, can I add
them with the gpg command with option "--group name=value1" or must I
re-enter all of the previous keys in addition to the new one?

If I want to remove only one person from the group, can I do that with
either the gpg command and "--ungroup name" or alternately remove their
key/name from the line in the gpg.conf file?

Do I have to add their public key to my keyring before I can add their key
to the group?

If a "group key" (a singular "group recipient") can be created through
either "--group" or the group line in the gpg.conf, and if I create a group,
then will only I have administrative control over who is added/removed from
the group, or will anybody in the group be able to add/remove anybody from
the group?

Thank you for your help!
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