``--decrypt=(true|auto|false)``
If ``true``, when encountering an encrypted message, try to
- decrypt it while reindexing. 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.
+ decrypt it while reindexing, 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.
+
+ If ``false``, notmuch reindex will also delete any stashed
+ session keys for all messages matching the search terms.
Be aware that the index is likely sufficient to reconstruct
the cleartext of the message itself, so please ensure that the