Hashing Engine Circuitry for SPHINCS+ Digital Signatures

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Solution Overview

Problem

Stateless hash-based signature operations, such as those according to the SPHINCS+ standard, face significant computation latency issues due to the need for numerous hash executions, which hinders their deployment in practical applications.

Innovation Solution

An optimized hardware engine with hashing circuitry is introduced, utilizing precomputed intermediate states for the SHA256 public key seed to reduce repetition and latency, and enabling parallelization of WOTS-Chain functions and tree traversal for Forest Of Random Subsets (FORS) functions, thereby accelerating key-generation, sign, and verify operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If numerous hash executions are performed for stateless hash-based signature operations, then security and correctness are ensured, but computation latency increases significantly

Engineering Contradiction:

Improvesignature operation correctnessVSAvoidcomputation latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent precomputes intermediate states for the SHA256 public key seed and stores them in a lookup table. During signature operations, these precomputed values are retrieved and used directly, eliminating the need to recompute them repeatedly. This preliminary computation and storage of intermediate states significantly reduces the computation latency while maintaining the security requirements of the SPHINCS+ standard.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If WOTS-Chain functions and tree traversal for FORS functions are executed sequentially, then implementation simplicity is maintained, but processing speed is reduced

Engineering Contradiction:

Improveimplementation simplicityVSAvoidprocessing speed

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent divides the signature operation into multiple independent parallel processing paths. Specifically, it separates the WOTS-Chain function computations from the FORS tree traversal operations, and further segments them into multiple parallel instances that can execute simultaneously. This segmentation allows the system to maintain implementation simplicity while achieving significant speedup through parallel execution of these segmented computational tasks.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250007727A1Hashing engine circuitry and methods for a sphincs digital signature operation

Publication Date: 2025.01.02 INTEL CORP

AI summary

Techniques for implementing a hardware engine for stateless hash-based signatures according to a SPHINCS+standard with encryption according to a SHA256 encryption standard are described. In certain examples, a system includes a processor core; and an accelerator coupled to the processor core, the accelerator comprising: one or more hash engine circuits, a coupling to allow for communication between the one or more hash engine circuits and a memory, and hash control circuitry to, for a request to perform a stateless hash-based signature operation on an input, cause performance of a one-time signature scheme function and a forest of random subsets function by the one or more hash engine circuits to generate a resultant.