Digital Item Access Control via Count-Driven Hashing

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Solution Overview

Problem

Conventional methods for limiting access to digital items are vulnerable to tampering, as modifying the access count file can grant unauthorized access, especially in systems with weak security measures.

Innovation Solution

Implementing a one-way hash function that associates a password hash with the access count, where the hash is generated and updated based on the number of permitted accesses, making it difficult to tamper with the count without matching the stored hash.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a simple access count file is used to limit accesses, then the ease of operation is improved, but the security is worsened as it is vulnerable to tampering

Engineering Contradiction:

Improveease of access controlVSAvoidsecurity against tampering

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent transforms the static access count into a dynamic parameter that drives password hash generation. Instead of storing only a count value, the system generates password hashes by applying a one-way hash function repeatedly based on the count value, creating a derived credential that changes with each access limitation cycle

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a password hash as an intermediary between the access count and the authentication process. This hash acts as a mediator that obscures the actual count value while still enabling access control validation, preventing direct manipulation of the count without knowing the original password

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the access count is stored in a file, then the device complexity is reduced, but the measurement precision of access control is worsened due to tampering risks

Engineering Contradiction:

Improvesimplicity of access control systemVSAvoidaccuracy of access count

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary hashing of the password combined with the access count before storage. By pre-computing the password hash based on the initial access count and storing this hashed value, the system creates a tamper-evident record that validates the actual number of accesses without exposing the raw count data

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If conventional access control methods are used, then the ease of manufacture is improved, but the reliability of access limitation is worsened due to vulnerability to unauthorized access

Engineering Contradiction:

Improveease of implementing access controlVSAvoideffectiveness of access limitation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the mechanical approach of storing and comparing plain text counts with a cryptographic hash-based system. Instead of directly managing access counts through file operations, the system uses one-way hash functions to create derived credentials that maintain access control functionality while providing mathematical guarantees against tampering

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9213851B2Limiting access to a digital item

Publication Date: 2015.12.15 VMWARE INC

AI summary

In a method for limiting access to a digital item, a count for the digital item is stored, wherein the count is a number of accesses permitted for the digital item. A password for accessing the digital item is received. A one-way hash function is performed on the password based on the number of accesses of the count to generate a password hash based on the count. The password hash is stored as the stored password hash.