In database security, what is meant by "data at rest" encryption?

"Data at rest" encryption refers to the practice of encrypting data while it's stored on disk. This ensures that even if someone gains unauthorized access to the physical storage medium, they won't be able to read the data without proper decryption keys. It's a crucial aspect of database security, protecting sensitive information from unauthorized access at rest. This encryption typically involves using algorithms and keys to convert plaintext data into ciphertext, rendering it unreadable without the appropriate decryption process. Hence, option 2 is correct.