How to add third party credentials for Plug Ins

I'm trying to use encryptvalue() and decryptvalue() in my existing rule. The purpose of using this function is to encrypt a value before inserting to Appian Cloud Database and decrypt a value when reading it from Appian Cloud Database. When trying to use encryptvalue(), I got an error saying ```Expression evaluation error at function 'encryptvalue' [line 2]: This plug-in [com.appiansolutionengineering.encryption] is not registered to access secured values for the given external system key [encryptdecryptkey]. Check the external systems plug-ins list in the Administration Console.``` Currently, I don't have any third party credentials nor Plug-Ins registered. How to use encryptvalue() and is there any other work around for encrypting data in Appian Cloud Database?