Variable-Strength Password Authentication for Computing Systems

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Solution Overview

Problem

Conventional authentication methods for computing systems require full password entry regardless of session length, leading to either poor security with short passwords or inconvenience with long passwords, especially in scenarios where frequent unlocking is necessary.

Innovation Solution

Implementing a variable-strength password system that requires a subset of the full password based on the elapsed time since the last unlock or the number of partial password unlocks, with password length progressively increasing as the time span or unlock count increases, and providing visual indicators to assist users.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a full password is required for every unlock, then security is maintained, but user convenience deteriorates during frequent short sessions

Engineering Contradiction:
ImprovesecurityVSAvoiduser convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements dynamic password requirements that adapt based on the locked state duration. The system transitions from requiring a full password for longer lock periods to accepting partial passwords for shorter lock periods, making the authentication process dynamic rather than static. This resolves the contradiction by adjusting security strength according to the actual risk level associated with different lock durations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the password parameter (length/complexity) based on the elapsed time in locked state. When the locked state exceeds a threshold duration, the full password is required; when it remains below the threshold, a partial password suffices. This parameter adaptation allows the system to maintain security for long locks while enabling quick access for short locks.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a short password is used, then user convenience is improved, but security deteriorates

Engineering Contradiction:
Improveuser convenienceVSAvoidsecurity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent makes the password requirement dynamic based on the locked state duration. The system automatically adjusts between short partial passwords and long full passwords depending on whether the lock period exceeds the threshold. This dynamic adjustment allows the system to use short passwords only when security risk is low (short lock periods) and enforce long passwords when risk is high (long lock periods).

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the password length parameter based on the threshold comparison. For locked states below the threshold, a shorter partial password is accepted; for locked states exceeding the threshold, the full longer password is required. This parameter change strategy allows the system to optimize both convenience and security based on actual usage patterns.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a long password is used, then security is improved, but user convenience deteriorates due to entry time

Engineering Contradiction:
ImprovesecurityVSAvoidpassword entry time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements a dynamic password length system that adjusts based on the locked state duration. The system requires full long passwords only when the lock period exceeds a certain threshold, while accepting short partial passwords for locks below the threshold. This dynamic approach minimizes password entry time for frequent short sessions while maintaining security for longer lock periods.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the required password length parameter based on the comparison between locked state duration and threshold. When locked state < threshold, partial password (shorter) is sufficient; when locked state > threshold, full password (longer) is required. This parameter adaptation reduces time loss for frequent unlocks while preserving security when needed.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2856381B1Variable-strength security based on time and/or number of partial password unlocks
Publication Date: 2016.12.07 GOOGLE LLC
  • EP2856381B1 patent drawingFigure 1A~1B
  • EP2856381B1 patent drawingFigure 2
  • EP2856381B1 patent drawingFigure 3A

AI summary

An authentication scheme for unlocking a computing system may require a shortened password in some cases. For example, the computing system may be configured to determine a time that a user has been locked out of a computing device and to determine which of a plurality of time spans that the time falls within. The computing system may also prompt the user for a required password including a full password or a subset of the full password depending on the determined time span. The computing system may be further configured to display a visual indicator corresponding to the determined time span or a required password length on a visual display. A length of the required password for login may be progressively longer for each of the plurality of time spans as a time period that a respective time span covers increases.