diff --git a/README.md b/README.md
index 45b184e..248b941 100644
--- a/README.md
+++ b/README.md
@@ -103,14 +103,14 @@ xh POST http://127.0.0.1:5567/datakey \
      comment='this is a test key 01'
 ```
 
-| Key              | Comment                                    |
-|------------------|--------------------------------------------|
-| type             | `aes`                                      |
-| spec             | ~~`128`, `192`,~~ `256` if `type` == `aes` |
-| exportable       | `true` or `false`                          |
-| return_plaintext | `true` or `false`                          |
-| name             | Data key name                              |
-| comment          | Data key comment                           |
+| Key              | Comment                                              |
+|------------------|------------------------------------------------------|
+| type             | `aes`                                                |
+| spec             | ~~`128`, `192`,~~ `256` if `type` == `aes`           |
+| exportable       | <i>[optional]</i> `true` or `false` , default `true` |
+| return_plaintext | <i>[optional]</i> `true` or `false`, default `false` |
+| name             | <i>[optional]</i> Data key name                      |
+| comment          | <i>[optional]</i> Data key comment                   |
 
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