Tweakable Hash Function Optimizing Register Storage in Post-Quantum Signatures

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Solution Overview

Problem

Existing hash-based signature schemes are inefficient in terms of hardware resource utilization, particularly register storage, and are vulnerable to quantum attacks, necessitating a transition to post-quantum cryptography that is both secure and efficient.

Innovation Solution

A tweakable hash function is defined to align chunk blocks of input data to fit within single input blocks, optimizing storage register usage and simplifying computation logic, thereby reducing the need for storage registers and improving computational efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If existing hash-based signature schemes are implemented using conventional hash functions, then the signing process can be performed, but hardware resource utilization is inefficient and excessive register storage is required

Engineering Contradiction:
Improveregister storageVSAvoidhardware resource utilization
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The input data is segmented into fixed-size chunk blocks (e.g., 128 bits each) that can be independently processed. This segmentation allows the hash function to process data in uniform units that fit efficiently into hardware registers, eliminating the need for excessive storage resources while maintaining the ability to handle arbitrary input sizes through iterative processing of these segmented blocks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a tweakable hash function where the hash computation parameters are dynamically adjusted based on the input data characteristics. By changing the internal parameters of the hash function (such as the tweak value derived from the message), the function can optimize its resource usage for different input scenarios, reducing register storage requirements while maintaining security properties.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If hash-based signature schemes are designed to be secure against quantum attacks, then post-quantum security is achieved, but hardware implementation efficiency and computational performance may deteriorate

Engineering Contradiction:
Improvequantum securityVSAvoidcomputational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The post-quantum secure hash-based signature scheme processes data in segmented chunk blocks, allowing the computationally intensive quantum-resistant operations to be broken down into manageable hardware-friendly units. This segmentation enables parallel processing and efficient resource utilization, maintaining computational efficiency while achieving quantum security through the underlying cryptographic construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tweakable hash function uses parameter adjustments to optimize the balance between security strength and computational efficiency. By dynamically tuning the hash function parameters (such as iteration counts, block sizes, and tweak values), the implementation can achieve quantum-resistant security levels while adapting to hardware capabilities to maintain acceptable computational performance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3910871B1Tweakable hash function in hash based signature schemes
Publication Date: 2025.09.03 CYSEC SA
  • EP3910871B1 patent drawingFigure 1
  • EP3910871B1 patent drawingFigure 2
  • EP3910871B1 patent drawing

AI summary

The present relates to a method for implementing a tweakable hash function to optimize hardware resource utilization used in hash-based signature schemes for signing a digital message. The method comprises : - i) Providing input data derived from the digital message to be signed; - ii) Segmenting the input data in chunk blocks; - iii) Generating an input sequence based on the chunk blocks, said input sequence being suitable for being provided to a hash computing engine, said computing engine comprising input blocks to receive the input sequence; - iv) Computing a tweakable hash function (T2) with a hash computing engine based on the input sequence to generate the tweaked hash value; The method is characterized in that the tweakable hash function is defined to sort the chunk blocks. The invention further relates to a device comprising a circuit arranged for executing a method according to the invention.