Which type of encryption is ideal for ensuring that only authorized users can access data after it has been stored?

Whole-instance encryption is a robust method designed to protect all data stored within a particular computing instance, ensuring that only users with the correct credentials can access that data. This form of encryption covers the entirety of the instance's storage, creating a comprehensive security blanket over all files and databases. By implementing whole-instance encryption, an organization can effectively safeguard its data both at rest and in transit, significantly enhancing the security posture of sensitive information.

This method is particularly useful in cloud environments, where data is stored across variable locations and systems. It centralizes access control, enabling organizations to manage who can decrypt and access the data. Consequently, if unauthorized users attempt to access the information, they will find it unreadable without the appropriate decryption keys, thus maintaining data confidentiality and integrity.

In contrast, while end-to-end encryption focuses on protecting data during transfer and ensuring that only the communicating users can read the messages, it does not inherently protect stored data. Public-key infrastructure is a framework used to manage encryption keys but is more about facilitating secure communications rather than directly protecting data at rest. Database encryption, on the other hand, secures data within individual databases but may not provide the holistic protection needed for entire instances that contain various types of data and applications.