The Platform Security Processor is a dedicated AMD security subsystem that runs separately from the main CPU cores. It handles trusted platform functions such as secure boot support, firmware checks, key management, and other low-level security tasks outside the normal operating-system flow. Because it sits below the OS, the PSP is part of the hardware root of trust: if it works correctly, it can help establish that the platform started in a known-good state.
In cyber security, the PSP matters because defenders rely on it for firmware integrity and platform attestation, while attackers may try to abuse bugs in PSP firmware, interfaces, or update paths to weaken those guarantees. A failure here is serious: software running in the OS may be unable to fully detect or repair compromise in this layer. In research on memory or firmware boundaries, PSP impact should be treated carefully unless directly demonstrated, because lower-level trust assumptions are often harder to test than ordinary application flaws.