chore: update readme

README.md

@@ -9,6 +9,11 @@ A plugin help you to copy your two-factor verify code in Powertoys Run
 1. Download plugin from Release
 2. Extract it to `%LOCALAPPDATA%\Microsoft\PowerToys\PowerToys Run\Plugins`
 
+## Upgrade
+1. Download plugin from Release
+2. Delete `%LOCALAPPDATA%\Microsoft\PowerToys\PowerToys Run\Plugins\TOTP` (Will not lose any data)
+3. Extract it to `%LOCALAPPDATA%\Microsoft\PowerToys\PowerToys Run\Plugins`
+
 ## Usage
 1. Add account 
 Plugin support standard OTPAuth URI (starts with `otpauth://`) and Google Authenticator Export URI(starts with `otpauth-migration://`), you can paste it to search bar and you will see option to add it to list. 
@@ -18,21 +23,29 @@ You can also add manually by edit config file in `%LOCALAPPDATA%\Microsoft\Power
  [
  {
  "Name": "Github: Hello",
- "Key": "12313"
+ "Key": "12313",
+ "IsEncrypted": false
  },
  {
  "Name": "Twitter: @Hello",
- "Key": "12313213"
+ "Key": "12313213",
+ "IsEncrypted": false
  }
  ]
  ```
- Change to config file will be applied immediately.
+ Change to config file will be applied immediately. 
+ Once plugin load config again, **all unencrypted data will be encrypted**.
 
 2. Delete account 
 There is no way to delete account by GUI. 
 You can edit file in `%LOCALAPPDATA%\Microsoft\PowerToys\PowerToys Run\Settings\Plugins\Zapic.Plugin.TOTP\TOTPList.json` to delete account you don't want. 
 Change to config file will be applied immediately.
 
+
+## About Encryption
+Plugin use `System.Security.Cryptography.ProtectedData` to encrypt every key. Key will be decrypted in memory if need. 
+Encrypted data only can be decrypted in your current machine with current account login, if you reinstall OS or change the account you login, the key cannot be decrypted.
+
 ## Build Plugin
 1. Clone repo
 2. Use "Publish" to build plugin and copy dependcies