+ ``--decrypt=(true|nostash|auto|false)``
+
+ If ``true``, when encountering an encrypted message, try to
+ decrypt it while indexing, and stash any discovered session
+ keys. If ``auto``, try to use any session key already known
+ to belong to this message, but do not attempt to use the
+ user's secret keys. If decryption is successful, index the
+ cleartext of the message.
+
+ Be aware that the index is likely sufficient (and the session
+ key is certainly sufficient) to reconstruct the cleartext of
+ the message itself, so please ensure that the notmuch message
+ index is adequately protected. DO NOT USE ``--decrypt=true``
+ or ``--decrypt=nostash`` without considering the security of
+ your index.
+
+ See also ``index.decrypt`` in **notmuch-config(1)**.
+
+EXIT STATUS
+===========
+
+This command supports the following special exit status code
+
+``75 (EX_TEMPFAIL)``
+ A temporary failure occurred; the user is invited to retry.
+