Hash Tree Authentication for Quantum-Resistant Security

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Solution Overview

Problem

Existing authentication schemes waste computing time due to the introduction of zeros to achieve even data levels in hash trees, particularly affecting short messages, and require large local memory for large messages, limiting device choice and causing speed penalties.

Innovation Solution

A method where hash functions receive message parts and previous hash outputs, ensuring even data at each level without zeros, and calculating tree parts sequentially to reduce memory usage and enhance processing speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If zeros are introduced to achieve even data levels in hash trees, then the authentication scheme can process any message length, but computing time is wasted particularly for short messages

Engineering Contradiction:
Improvemessage length adaptabilityVSAvoidcomputing time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments the message into pairs of blocks and processes them through hash functions in a tree structure. By organizing the processing in this segmented manner, the system can handle any message length without requiring padding zeros, as each segment is processed independently through the hash tree levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter approach from fixed even-length requirements to variable-length handling by processing message blocks in pairs. This parameter change allows the system to adapt to any message length while maintaining efficient processing without the time loss associated with zero-padding in traditional approaches.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If large local memory is used to store tree data for large messages, then authentication can be performed without multiple data transports, but device choice is restricted and speed penalties occur

Engineering Contradiction:
Improveauthentication speedVSAvoidmemory requirements
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the authentication process into levels that can be processed sequentially or in stages. This segmentation allows the system to process large messages without requiring the entire tree data to be stored in local memory at once, enabling authentication on devices with limited memory while maintaining high processing speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary processing of message blocks into pairs and prepares them for hash function processing in a manner that reduces the immediate memory footprint. This preliminary organization allows efficient processing without requiring large amounts of local memory to be allocated for the entire authentication tree.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If traditional public cryptographic standards are used, then authentication is based on hard mathematical problems, but security evidence is insufficient and quantum computers may break the standards

Engineering Contradiction:
Improveauthentication securityVSAvoidquantum computer vulnerability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mathematical cryptography system with an information-theoretic authentication system based on hash functions. This substitution moves the security foundation from computational hardness (vulnerable to quantum computers) to information theory principles that provide unconditional security against any computational adversary, including quantum computers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the security parameter from computational complexity (based on hard mathematical problems) to information-theoretic security. This parameter change fundamentally alters the security model, providing authentication that is secure against quantum computers and any future computational advances, as it relies on information theory rather than computational assumptions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3588841B1Method and device for executing an authentication scheme
Publication Date: 2025.11.12 QUBALT GMBH
  • EP3588841B1 patent drawingFigure 1
  • EP3588841B1 patent drawingFigure 2
  • EP3588841B1 patent drawingFigure 3

AI summary

A method for executing an authentication scheme with a sender entity (10) and a receiver entity (20) is proposed, the method comprising: authenticating (201) a message (M) having a plurality of message parts (m0-m10) using a tree (T) of first hash functions (h1-h10) representing a hash function family of second hash functions, including: inputting (202) the message parts (m0-m10) into the tree (T) and calculating the first hash functions (h1-h10) for providing a hash value as an output (010) of said tree (T), wherein, in at least one of the first hash functions (h1-h10), one of the message parts (m0-m10) and an output (01-09) of one of the other first hash functions (h1-h9) are input.