- ``--decrypt=(true|false)``
-
- If true and the message is encrypted, try to decrypt the
- message while indexing. If decryption is successful, index
- the cleartext itself. Either way, the message is always
- stored to disk in its original form (ciphertext). Be aware
- that the index is likely sufficient to reconstruct the
- cleartext of the message itself, so please ensure that the
+ ``--decrypt=(true|auto|false)``
+
+ If ``true`` and the message is encrypted, try to decrypt the
+ message while indexing, storing any session keys discovered.
+ If ``auto``, and notmuch already knows about a session key for
+ the message, it will try decrypting using that session key but
+ will not try to access the user's secret keys. If decryption
+ is successful, index the cleartext itself. Either way, the
+ message is always stored to disk in its original form
+ (ciphertext).
+
+ Be aware that the index is likely sufficient to reconstruct
+ the cleartext of the message itself, so please ensure that the