What is a Self-Encrypting Drive (SED)?

• A. HDD or SSD with an encryption circuit built into the drive.
• B. A firewall feature for inbound traffic.
• C. A behavior analytics tool.
• D. Self-Encrypting Drive (SED) is a HDD or SSD with an encryption circuit built into the drive.

Answer: (D)

A Self-Encrypting Drive is a hard disk or solid-state drive that has encryption hardware built into the drive itself. Data is automatically encrypted as it’s written and decrypted as it’s read, with the encryption key stored in the drive’s own hardware, so the data remains unreadable at rest if the drive is removed or accessed by unauthorized systems. This direct, built-in definition is why the option stating Self-Encrypting Drive is a HDD or SSD with an encryption circuit built into the drive is the best fit. The other descriptions point to unrelated concepts (firewall features or behavior analytics) or merely restate the mechanism without naming the concept. For stronger security, you’d typically combine SED with authentication (like pre-boot or drive passwords) so the data can’t be decrypted without proper credentials, and you might see standards such as Opal or ATA security backing the implementation.