Which statement best contrasts encryption at rest and encryption in transit?

Which statement best contrasts encryption at rest and encryption in transit?

• A. Encryption at rest protects data in motion; encryption in transit protects stored data
• B. They are interchangeable
• C. Only encryption at rest matters in CDX
• D. Encryption at rest protects stored data and encryption in transit protects data moving over networks; both are essential

Answer: (D)

Encryption protects data in two states: at rest and in motion. Encryption at rest keeps stored data unreadable on disks, databases, or backups, so even if storage is accessed by an unauthorized party, the content remains protected. Encryption in transit secures data as it travels over networks, using protocols like TLS to prevent eavesdropping, tampering, or impersonation during transmission. The statement that matches this separation and emphasizes both parts is the best choice because it communicates that each form of encryption protects a different phase of the data life cycle and that both are essential. The other options mix up the roles, claim they are interchangeable, or downplay one form of protection, which would leave gaps in security.

Encryption protects data in two states: at rest and in motion. Encryption at rest keeps stored data unreadable on disks, databases, or backups, so even if storage is accessed by an unauthorized party, the content remains protected. Encryption in transit secures data as it travels over networks, using protocols like TLS to prevent eavesdropping, tampering, or impersonation during transmission. The statement that matches this separation and emphasizes both parts is the best choice because it communicates that each form of encryption protects a different phase of the data life cycle and that both are essential. The other options mix up the roles, claim they are interchangeable, or downplay one form of protection, which would leave gaps in security.