developer video for a developer wants to securely store an access token that allows a transaction-processing application running on Amazon EC2 instances to
A developer wants to securely store an access token that allows a transaction-processing application running on Amazon EC2 instances to authenticate and send a chat message (via the chat API) to the company's support team when an invalid transaction is detected. While minimizing management overhead, the chat API access token must be encrypted both at rest and in transit, and also be accessible from other AWS accounts. What is the most efficient solution to address this scenario?