In the context of AWS Security Best Practices for RDS, if you require encryption or data integrity authentication of data at rest for compliance or other purposes, you can add protection at the _____ using SQL cryptographic functions.
physical layer
security layer
application layer
data-link layer
Explanations:
The physical layer refers to the hardware level, which is managed by AWS for encryption at rest, but not by SQL cryptographic functions.
The security layer relates to network security and identity management, not directly to SQL cryptographic functions used for data protection.
The application layer is where SQL cryptographic functions are used to implement data encryption and integrity for data at rest.
The data-link layer involves network protocols and hardware addressing, not relevant to SQL cryptographic functions for data protection.