John wants to protect data at rest so that he can process it and use it as needed in its original form. What solution from the following list is BEST suited to this requirement?

Encryption is often used to protect data at rest. When data needs to be accessed, it can be decrypted. Hashing is not reversible, meaning that it is not used for data storage when the original form is needed for processing. Comparing hashed passwords works because the password is presented again, rather than the password needing to be retrieved from storage. TLS is used to protect data in motion, and tokenization is a data security technique that replaces sensitive data elements with nonsensitive elements that can still be processed in useful ways.