What type of cryptoprocessor can support reducing a computer's attack surface?

The most suitable option for reducing a computer's attack surface is a trusted platform module (TPM). A TPM is a specialized hardware-based cryptoprocessor designed to secure hardware by integrating cryptographic keys into devices. It enhances the security posture of a system in several ways, including providing a platform for secure boot processes and ensuring the integrity of the system from the moment it is powered on.

By using TPM, critical data such as encryption keys can be secured away from potential vulnerabilities present in software, as the keys are stored in a hardware component that is resistant to tampering. This hardware security mechanism helps mitigate the risks associated with software attacks, thereby reducing the overall attack surface of the computer.

While hardware security modules (HSMs) also play an important role in cryptographic processes and securing sensitive data, their primary function is to manage encryption keys and perform cryptographic operations rather than focusing on the general computer's operational environment and integrity. Public key infrastructure (PKI) and certificate revocation lists (CRL) are related to managing security frameworks using certificates, but they do not directly contribute to reducing a system's attack surface.