Partial Hash Authentication for Picture Passwords

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Solution Overview

Problem

Conventional authentication methods based on picture passwords can be computationally intensive and resource-heavy, especially when dealing with complex image grids and anti-aliasing techniques, leading to increased complexity and potential security vulnerabilities.

Innovation Solution

A client device that calculates and compares partial hashes of user input actions with a proof of knowledge server, reducing the need to send all possible hashes and utilizing a hexagonal grid to decrease the number of possible sequences, thereby minimizing resource consumption and processing time while maintaining security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional authentication methods use picture passwords with implicit grids and anti-aliasing techniques, then authentication capability is improved, but computational complexity and resource consumption increase

Engineering Contradiction:
Improveauthentication capabilityVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the hash verification process into two parts: the server computes and stores only a portion of the hash (first N bits), while the client computes the remaining portion locally. This segmentation reduces the server's computational burden and storage requirements while maintaining authentication security, as the client can verify authentication by comparing its computed hash portion with the server's stored portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by having the server compute and store only a partial hash (first N bits) rather than the complete hash. This partial computation approach reduces the server's resource consumption while still providing sufficient security, as the client must compute the full hash and the server verifies the critical portion.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If the server computes and stores complete hashes for all possible input sequences, then authentication security is improved, but server resource consumption increases

Engineering Contradiction:
Improveauthentication securityVSAvoidserver resource consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential portion of the hash (first N bits) for server storage and verification, removing the need to store and process complete hashes for all possible input sequences. This extraction approach maintains authentication security while significantly reducing server resource consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The server performs partial computation by calculating and storing only the first N bits of the hash rather than complete hashes. This partial action reduces server energy consumption and storage requirements while maintaining sufficient security through client-side verification.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If the system processes all possible input sequences for anti-aliasing, then authentication accuracy is improved, but processing time increases

Engineering Contradiction:
Improveauthentication accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the server pre-compute and store the first N bits of the hash for all possible input sequences during system setup. This preliminary computation eliminates the need for real-time processing of all sequences during authentication, significantly reducing processing time while maintaining authentication accuracy.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3149644B1Device and server for password pre-verification at client using truncated hash
Publication Date: 2018.08.01 ANTIQUE BOOKS INC
  • EP3149644B1 patent drawingFigure 1
  • EP3149644B1 patent drawingFigure 2
  • EP3149644B1 patent drawingFigure 3

AI summary

Antialiasing for picture passwords and other touch displays is disclosed. In some embodiments a client device for authenticating a user is operable to obtain a sequence of input actions for an image and obtain a partial hash from a Proof of Knowledge (PoK) server where the partial hash is part of a hash used for authentication of the user. The client device is also operable to calculate a hash for the sequence and determine if a part of the hash matches the partial hash. If the part of the hash matches the partial hash, the client device sends a communication to the PoK server to authenticate the user based on the hash for the sequence of the one or more input actions and obtain a response indicating whether the user is authenticated. In this way, sending some hashes to the proof of knowledge server may not be necessary, saving resources.