What are key helpers?

[Daniel Kahn Gillmor]

On Thu 2016-02-25 09:21:45 +0100, Josef Carnap <carnap at gmx.at> wrote:

> In the option desription of --exec-path and in some descriptions of
> other options as well I can read of "Key helpers".
> What kind of program is a key helpers? Are key helpers part of the GnuPG
> suite oder are they external programs?

they're separate programs that operate over more-or-less well-defined
interfaces (stdin/stdout text-based interaction, usually), most of which
are shipped as part of the GnuPG suite.

> Does anybody know some examples and for wehat purposes one could use hey
> helpers?

take a look at the execpath in your installed system
(e.g. /usr/lib/gnupg/ or /usr/lib/gnupg2/ on debian systems) for
examples.  many of the helpers in gnupg 1.4.x are related to connections
to keyservers.  in 2.1.x all the network connections are handled by
dirmngr, so they aren't needed.

in 2.0.x and 2.1.x, gpg-check-pattern is an example -- its --help
output shows:

-----------
Syntax: gpg-check-pattern [options] patternfile
Check a passphrase given on stdin against the patternfile

Options:
 
 -v, --verbose   verbose
     --check     run only a syntax check on the patternfile
 -0, --null      input is expected to be null delimited
-----------

hth,

        --dkg