diff --git a/TinyEncryptSpecV1.1.md b/TinyEncryptSpecV1.1.md
index abfde2c..9c4b5bd 100644
--- a/TinyEncryptSpecV1.1.md
+++ b/TinyEncryptSpecV1.1.md
@@ -17,8 +17,8 @@ Meta format:
 | version | String  | Constant value: `1.1`                        |
 | created | Long    | Created time, Unix Epoch                     |
 | userAgent | String  | User Agent, e.g. `TinyEncrypt v0.5.1@MacOS`  |
-| comment | String  | Plain text comment                           |
-| encryptedComment | String  | Encrypted comment                            |
+| comment | String  | `optinonal` Plain text comment               |
+| encryptedComment | String  | `optinonal` Encrypted comment                |
 | pgpEnvelop | String  | `deprecated` PGP Publickey Encrypted DataKey |
 | pgpFingerprint | String  | `deprecated` Hex(Sha256(PGP Publickey))      |
 | envelop | String  | `deprecated` KMS Encrypted DataKey           |