/* Construct a new MIME node pointing to the root message part of
* message. If crypto->verify is true, signed child parts will be
* verified. If crypto->decrypt is NOTMUCH_DECRYPT_TRUE, encrypted
- * child parts will be decrypted. If the crypto contexts
+ * child parts will be decrypted using either stored session keys or
+ * asymmetric crypto. If crypto->decrypt is NOTMUCH_DECRYPT_AUTO,
+ * only session keys will be tried. If the crypto contexts
* (crypto->gpgctx or crypto->pkcs7) are NULL, they will be lazily
* initialized.
*