Hierarchical Hash Tree Authentication for Block-Based Media
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Solution Overview
Problem
Existing authentication methods for DVD and similar media technologies face challenges in balancing security with performance, as they often require slow RSA verification, high overhead, or custom disk manufacturing, and may not provide adequate security due to single secret key mechanisms or increased latency.
Innovation Solution
A hierarchical hashing technique using a binary or non-binary tree structure with one-way hash functions like SHA-1, where authentication data is integrated with data blocks and validated through a hierarchical hash tree, allowing selective authentication and minimizing read overhead, while supporting mass production and read-only media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RSA signature verification is used for each block, then authentication security is improved, but verification speed deteriorates
Solution Approach 1:
The patent segments the authentication verification process into two distinct phases: a fast phase during playback where only lightweight hash comparisons are performed against pre-computed hashes, and a slow phase during initial loading where the computationally intensive RSA verification is performed. This segmentation allows the system to achieve both high security through RSA signatures and fast playback through efficient hash-based verification.
Solution Approach 2:
The patent performs the computationally expensive RSA verification and hash computation in advance during the initial loading phase, storing the results in a lookup table. This preliminary action eliminates the need for slow RSA verification during subsequent playback, allowing the system to use fast hash comparisons instead while maintaining security.
2Reliability
If block signatures are attached to every data block, then authentication coverage is improved, but disk overhead increases
Solution Approach 1:
The patent applies different authentication mechanisms to different parts of the data structure based on their specific requirements. Hash signatures are attached to individual data blocks for fine-grained authentication, while a separate root hash provides overall data structure authentication. This localized approach ensures comprehensive coverage without uniformly applying heavy cryptography to all data.
Solution Approach 2:
The hash values serve multiple functions simultaneously: they authenticate individual data blocks, enable selective verification of specific blocks during playback, and when combined with the root hash, provide authentication for the entire data structure. This multi-functionality reduces the need for separate authentication mechanisms and minimizes overall overhead.
3Ease of manufacture
If HMAC with single secret key is used for all disks, then manufacturing complexity is reduced, but security level deteriorates
Solution Approach 1:
The patent segments the key management into two distinct components: a public key that can be universally distributed and used for verification, and a private key that remains secret and is used only during the initial loading phase. This segmentation allows the same public key to be used across all disks (simplifying manufacturing) while maintaining security through the private key's secrecy and limited usage scope.
Solution Approach 2:
The patent performs the secure HMAC authentication with the private key during the initial loading phase before any data is accessed. Once this preliminary authentication is complete and the data is loaded into memory, the system transitions to using the public key for verification, eliminating the need for continuous secret key usage and simplifying manufacturing while maintaining security.
4Reliability
If hierarchical signature approach is used, then authentication structure is improved, but access latency increases
Solution Approach 1:
The patent segments the authentication verification into two distinct phases: an initial loading phase where the complete hierarchical authentication structure is built and stored in a lookup table, and a playback phase where only simple hash comparisons are performed. This segmentation separates the computationally intensive structure building from the fast verification operations, minimizing latency during data access.
Solution Approach 2:
The patent performs the construction of the hierarchical authentication structure and pre-computation of hash values during the initial loading phase. By performing this preliminary action in advance and storing results in a lookup table, the system eliminates the need for complex hierarchical verification during subsequent data access operations, significantly reducing access latency while maintaining robust authentication.
Data Source
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AI summary
A technique for security and authentication on block-based media includes involves the use of protected keys, providing authentication and encryption primitives. A system according to the technique may include a secure device having a security kernel with protected keys. A disk drive security mechanism may support authentication of data, secrecy, and ticket validation using the security kernel and, for example, a ticket services module (e.g., a shared service that may or may not be used by other storage devices like flash).