File: gnupg.info,  Node: Agent GET_PASSPHRASE,  Next: Agent CLEAR_PASSPHRASE,  Prev: Agent ISTRUSTED,  Up: Agent Protocol

2.6.7 Ask for a passphrase
--------------------------

This function is usually used to ask for a passphrase to be used for
symmetric encryption, but may also be used by programs which need
special handling of passphrases.  This command uses a syntax which helps
clients to use the agent with minimum effort.

       GET_PASSPHRASE [--data] [--check] [--no-ask] [--repeat[=N]] \
                      [--qualitybar] CACHE_ID                \
                      [ERROR_MESSAGE PROMPT DESCRIPTION]

   CACHE_ID is expected to be a string used to identify a cached
passphrase.  Use a 'X' to bypass the cache.  With no other arguments the
agent returns a cached passphrase or an error.  By convention either the
hexified fingerprint of the key shall be used for CACHE_ID or an
arbitrary string prefixed with the name of the calling application and a
colon: Like 'gpg:somestring'.

   ERROR_MESSAGE is either a single 'X' for no error message or a string
to be shown as an error message like (e.g.  "invalid passphrase").
Blanks must be percent escaped or replaced by '+''.

   PROMPT is either a single 'X' for a default prompt or the text to be
shown as the prompt.  Blanks must be percent escaped or replaced by '+'.

   DESCRIPTION is a text shown above the entry field.  Blanks must be
percent escaped or replaced by '+'.

   The agent either returns with an error or with a OK followed by the
hex encoded passphrase.  Note that the length of the strings is
implicitly limited by the maximum length of a command.  If the option
'--data' is used, the passphrase is not returned on the OK line but by
regular data lines; this is the preferred method.

   If the option '--check' is used, the standard passphrase constraints
checks are applied.  A check is not done if the passphrase has been
found in the cache.

   If the option '--no-ask' is used and the passphrase is not in the
cache the user will not be asked to enter a passphrase but the error
code 'GPG_ERR_NO_DATA' is returned.

   If the option '--qualitybar' is used and a minimum passphrase length
has been configured, a visual indication of the entered passphrase
quality is shown.

       CLEAR_PASSPHRASE CACHE_ID

   may be used to invalidate the cache entry for a passphrase.  The
function returns with OK even when there is no cached passphrase.