Which process uses platform configuration registers (PCRs) in the TPM during the boot process to ensure system integrity but is not related to encrypting data at rest?

The process that utilizes platform configuration registers (PCRs) in the Trusted Platform Module (TPM) during the boot sequence to confirm system integrity is called measured boot. This process is crucial because it ensures that the components involved in the boot process are genuine and have not been tampered with, allowing the system to assess its integrity by measuring the software and firmware before execution.

Measured boot captures cryptographic hashes of the boot components (such as firmware and bootloader) and stores these measurements in the PCRs of the TPM. This security mechanism allows for verification against known good configurations, helping to detect any unauthorized changes. If any measurements do not match what is expected, it indicates a potential compromise of the system's integrity.

This process is distinct from the other options as it does not focus on encrypting data at rest. Instead, its primary purpose is to establish a trusted and secure boot environment. In contrast, the other choices relate to different aspects of security; TPM itself is the hardware platform that supports the measured boot process, HSM relates to broader cryptographic key management, and SEDs are specifically designed for encrypting data stored on drives.