Protection of Private Keys with TPM 2.0

In today's digital era, web servers play a critical role in ensuring data security, user trust, and compliance with regulations. They are the gatekeepers of web content, enabling encrypted communication, data integrity, and reliable content delivery. Among the leading web servers, Nginx, Apache, and Cloudflare Server top the list. Web servers are essential in the face of increasing cyber threats, providing safeguards through access control, availability, and data confidentiality and integrity. Access control is facilitated by authentication and authorisation, while availability is achieved through mechanisms like fault tolerance and scaling. Data confidentiality is upheld via encryption and Transport Layer Security for secure connections, while data integrity is preserved with the help of public key infrastructure (PKI) and digital certificates. Implementing TLS with OpenSSL in Nginx and Apache is crucial for secure, encrypted communication. This security layer ensures data protection, user trust, and regulatory compliance. It enhances website credibility and overall security, defending against cyber threats and future-proofing web services. Safeguarding cryptographic keys, a complex challenge due to the need for data decryption, can be addressed by using secure storage mechanisms, such as Hardware Security Modules (HSMs), Trusted Platform Modules (TPMs), Key vaults, or Trusted Key Management Systems (KMS). TPMs are tamper-resistant cryptoprocessors adhering to international standards, designed to enhance hardware security. They store aggregated measurements in Platform Configuration Registers (PCRs) and offer cryptographic records of the software state. Sealing/Unsealing operations ensure secure key storage and retrieval, and the solution based on Sealing objects enhances private key security. The proposed solution employs the Sealing operation to protect private keys in an Apache server, ensuring they can only be retrieved using the TPM while adhering to the conditions imposed by the PCRs. The solution, developed through source code modifications, offers a strong balance between security and resource efficiency, achieving a robust defence against cyber threats like brute force and dictionary attacks. The ability to use TPM 2.0 for private key protection can also be extended to web servers like Nginx, making this approach highly versatile. In conclusion, the presented solution leverages TPM 2.0 to enhance the security of private keys in Apache servers, using PCRs for system attestation. This solution, adaptable for Nginx and any OpenSSL-based web server, offers a robust security mechanism for safeguarding critical cryptographic assets.