Secure Boot Process Using TPM for Data Access Control
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Solution Overview
Problem
Current secure boot processes for computers are vulnerable to attacks during the loading of the operating system, which can compromise decryption keys and expose sensitive data, especially during machine transfers or sales, due to potential human errors in enabling secure boot features.
Innovation Solution
Implementing a secure boot process using a Trusted Platform Module (TPM) that encrypts and manages decryption keys, ensuring their integrity by verifying correct measurements before unsealing them, and providing backup secrets for access in case of primary failure, while also disabling secrets to prevent future access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual file encryption is used to control access to sensitive data, then data security is improved, but ease of operation deteriorates due to the need to encrypt and decrypt files manually each time access is desired
Solution Approach 1:
The system performs preliminary encryption of entire data volumes or partitions at the time of setup, rather than requiring manual encryption of individual files when needed. The TPM chip stores encryption keys and automatically manages the encrypted state of data, so users only need to perform a one-time authentication during system startup to access all their encrypted data without repeating manual encryption/decryption operations.
2Ease of operation
If a secure logon process is implemented to protect user profiles, then access control to sensitive data is improved, but security reliability deteriorates due to loopholes that allow attackers to circumvent the logon process or access stray data left on transferred machines
Solution Approach 1:
The TPM chip acts as an intermediary security layer between the user and the operating system. It independently verifies the authenticity of boot components and manages encryption keys separate from the OS logon process. This mediator ensures that even if the OS logon is circumvented, the TPM will not release decryption keys unless proper authentication occurs, closing the security loophole.
Solution Approach 2:
The system performs preliminary security verification during the boot process before the OS logon even occurs. The TPM checks the integrity of boot components and establishes an early security boundary, ensuring that no unauthorized code can load before the security infrastructure is in place. This preliminary action prevents attackers from circumventing logon by injecting malicious code during system startup.
3Reliability
If the operating system is loaded with protection infrastructure to prevent attacks, then security reliability is improved, but the time before protection is established deteriorates, leaving the system vulnerable during the loading phase
Solution Approach 1:
The TPM performs security verification and establishes protection infrastructure during the very first stages of system startup, before the main operating system loads. By measuring and verifying the integrity of boot components early in the boot process, the security infrastructure is established immediately rather than waiting for the full OS to load, minimizing the vulnerable time window.
Solution Approach 2:
The security verification process is segmented into discrete measurement steps that occur at different stages of booting. The TPM measures individual components (BIOS, boot loader, OS kernel) separately and accumulates trust incrementally. This segmentation allows security protection to be established in phases, with each verified component providing a layer of protection as the system boots, rather than waiting for complete OS loading.
4Object-affected harmful factors
If decryption keys are protected by the logon procedure with limited authentication attempts, then security against brute force attacks is improved, but security reliability deteriorates if a rogue loader compromises the logon program or enables key usage without proper credentials
Solution Approach 1:
The TPM chip serves as an intermediary that separates key storage and key release authorization from the OS logon program. It independently verifies authentication credentials and controls key release, preventing rogue loaders from compromising the logon program. The TPM's limited authentication attempt counter operates independently within the secure hardware boundary, so even if the OS logon is compromised, the TPM will not release keys after failed attempts.
Solution Approach 2:
The patent replaces the software-based logon protection mechanism with a hardware-based TPM system. The physical TPM chip provides tamper-resistant key storage and authentication verification, substituting the vulnerable software logon program with a hardware security boundary. This mechanical/hardware substitution ensures that authentication attempts and key release are controlled by physical security boundaries rather than software that can be compromised by rogue loaders.
Data Source
AI summary
Systems and methods for controlling access to data on a computer with a secure boot process can provide a highly efficient mechanism for preventing future access to encrypted digital resources. This may be advantageous in a range of scenarios, for example where a computer is sold and assurance is desired that no stray private data remains on the hard disk. Data resources, for example all data associated with one or more particular hard disk partitions, may be encrypted. The decryption key may be available through a secure boot process. By erasing, altering, or otherwise disabling a secret, such as a decryption key or a process that obtains a decryption key, the data formerly accessible using such secret becomes inaccessible.