A developer is writing a client application that encrypts sensitive data using a data key before sending it to a server application. The client application sends the data key to the server application so that the server application can decrypt the sensitive information. The developer is concerned that the confidentiality of the sensitive data might be compromised if the data key is stolen. Which type of encryption should the developer use to fully protect the sensitive information? Asymmetric encryption Server$-$side encryption Symmetric encryption Envelope encryption