Encoded Hash Message Authentication Code Re-keying
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Solution Overview
Problem
In large data storage systems, re-computing message authentication codes (MACs) is computationally expensive and time-consuming when secret keys need to be changed, especially when dealing with gigabytes or terabytes of data, as conventional methods require processing the entire data set through a cryptographic function.
Innovation Solution
The implementation of an encoded hash message authentication code (EHM) system that allows for re-keying with minimal computational effort, using a collision-resistant hash function and a pseudo-random permutation operation, enabling re-computation of MACs without re-applying the data set to the hash operation, thus maintaining constant computational cost per tag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MAC operations are used to re-compute authentication tags when changing secret keys, then security is maintained, but processing time and computational resources increase significantly
Solution Approach 1:
The authentication tag computation is segmented into two parts: a data-independent component (hash of the key) and a data-dependent component (XOR with hash of data). This segmentation allows the data-independent part to be pre-computed and stored, eliminating the need to re-process the entire data set when keys change.
Solution Approach 2:
The patent performs preliminary computation of the hash of the data and stores it alongside the authentication tag. When re-keying is needed, this pre-computed hash is reused, avoiding the need to re-hash the entire data set and significantly reducing processing time.
2Reliability
If conventional MAC operations are used to re-compute authentication tags when changing secret keys, then authentication integrity is preserved, but processing resources are consumed considerably
Solution Approach 1:
The authentication mechanism is segmented into pre-computed components (hash of data, hash of key) and final combination (XOR operation). This segmentation allows the computationally intensive hashing to be performed only once, while key changes only require lightweight XOR operations on pre-computed values.
Solution Approach 2:
The patent creates and stores a copy of the hash of the data separately from the authentication tag. This copy can be reused during re-keying operations without re-processing the original data, significantly reducing processing resource consumption while maintaining authentication integrity.
3Use of energy by moving object
If lazy revocation is used to postpone re-computation of MAC, then processing resources are saved, but security assumptions about limited adversary access must be made
Solution Approach 1:
The patent performs preliminary computation and storage of data hashes before they are needed for re-keying. This allows the system to maintain strong security guarantees while avoiding the need to re-process data, eliminating the need for lazy revocation and its associated security assumptions.
Data Source
AI summary
Data storage and message processing using an encoded hash message authentication code is described. In one embodiment, a data processing apparatus comprises one or more processors; logic coupled to the one or more processors for execution and which, when executed by the one or more processors, causes receiving a data set at the one or more processors; creating and storing a hash output value by applying the data set to a collision-resistant hash operation that provides the hash output value as output; encoding the hash output value using a uniquely invertible keyed pseudo-random permutation operation based on a first shared key, to result in creating an encoded authentication code; and associating the encoded authentication code with the data set.