add a way to disable tag encryption

ReadMe.md

@@ -99,6 +99,24 @@ encrypt: # hexo-blog-encrypt
 
 ```
 
+#### To disable tag encryption
+
+Just let the `password` property in front matter to `""`.
+
+Example:
+
+```
+---
+title: Callback Test
+date: 2019-12-21 11:54:07
+tags:
+    - A Tag should be encrypted
+password: ""
+---
+
+Use a "" to diable tag encryption.
+```
+
 ### Config priority
 
 post's front matter > `_config.yml` (in the root directory) > default

ReadMe.zh.md

@@ -105,6 +105,24 @@ encrypt: # hexo-blog-encrypt
 
 ```
 
+#### 对博文禁用 Tag 加密 
+
+只需要将博文头部的 `password` 设置为 `""` 即可取消 Tag 加密.
+
+Example:
+
+```
+---
+title: Callback Test
+date: 2019-12-21 11:54:07
+tags:
+    - A Tag should be encrypted
+password: ""
+---
+
+Use a "" to diable tag encryption.
+```
+
 ### 配置优先级
 
 文章信息头 > `_config.yml` (站点根目录下的) > 默认配置

index.js

@@ -24,6 +24,11 @@ hexo.extend.filter.register('after_post_render', (data) => {
   let password = data.password;
   let tagUsed = false;
 
+  // use a empty password to disable category encryption
+  if (password === "") {
+    return data;
+  }
+
   if (hexo.config.encrypt === undefined) {
     hexo.config.encrypt = [];
   }

package.json

@@ -34,7 +34,7 @@
     "test": "echo \"Error: no test specified\" && exit 1",
     "lint": "eslint --ext .js ./"
   },
-  "version": "3.0.12",
+  "version": "3.0.13",
   "devDependencies": {
     "eslint": "^6.2.2"
   }