- index the cleartext. If ``auto``, it will try to index the
- cleartext if a stashed session key is already known for the message,
- but will not try to access your secret keys. Use ``false`` to
- avoid decrypting even when a session key is already known.
-
- Be aware that the notmuch index is likely sufficient to
- reconstruct the cleartext of the message itself, so please
- ensure that the notmuch message index is adequately protected.
- DO NOT USE ``index.decrypt=true`` without considering the
- security of your index.
-
- Default: ``false``.
+ index the cleartext, stashing a copy of any discovered session
+ keys for the message. If ``auto``, it will try to index the
+ cleartext if a stashed session key is already known for the message
+ (e.g. from a previous copy), but will not try to access your
+ secret keys. Use ``false`` to avoid decrypting even when a
+ stashed session key is already present.
+
+ ``nostash`` is the same as ``true`` except that it will not
+ stash newly-discovered session keys in the database.
+
+ Be aware that the notmuch index is likely sufficient (and a
+ stashed 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
+ ``index.decrypt=true`` or ``index.decrypt=nostash`` without
+ considering the security of your index.
+
+ Default: ``auto``.