You are designing a mobile chat application and need to ensure that users cannot spoof chat messages by falsely claiming a message was sent by a specific user. What should you do?

Exam-Like

Tag messages client side with the originating user identifier and the destination user.

Encrypt the message client side using block-based encryption with a shared key.

Use public key infrastructure (PKI) to encrypt the message client side using the originating user's private key.

Use a trusted certificate authority to enable SSL connectivity between the client application and the server.

Google Professional Cloud Architect