The extension SignJSONUsingHS256 is used for signing a text using HS256 scheme. It has two server action Signing and VerifyAndDecrypt.

The first server action expects JSON/normal text as input and key that will be used for signing the input text. In response this action gives signed text which has three parts, Header-Payload-Signature. we can use this and pass as request in secure API calls such as that of Payment Gateway.

The next action is the VerifyAndDecrypt, this action verify whether the given signed payload is correct and if it is verified, It'll decrypt it and return us the Original JSON/text.