Adaptive Session Lifetime Based on Reputation

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Solution Overview

Problem

There is a tension between security and usability in session lifetimes, as short lifetimes enhance security but are less convenient, while long lifetimes compromise security.

Innovation Solution

Implementing an adaptive session lifetime system that dynamically determines session duration based on factors like sign-in risk, device risk, and resource sensitivity, using a reputation component to generate tokens with varying validity periods, and re-evaluating these periods as conditions change.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a short session lifetime is used, then security is improved, but usability deteriorates due to frequent reauthentication

Engineering Contradiction:
ImprovesecurityVSAvoidusability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements dynamic session lifetime adjustment by transitioning from a fixed session duration to an adaptive model that modifies session validity periods based on real-time risk assessments. The session management system continuously monitors user behavior, device characteristics, and contextual factors, then dynamically extends or shortens session lifetimes to balance security requirements with user convenience, eliminating the need for frequent reauthentication in low-risk scenarios while maintaining short lifetimes in high-risk contexts.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the session lifetime parameter adaptively based on risk factor analysis. Instead of using a static time value, the session duration is adjusted as a variable parameter that responds to changes in security conditions, user behavior patterns, and device trust levels. This allows the session lifetime to be extended beyond the default short duration when risk assessments indicate safety, thereby reducing reauthentication frequency without compromising security.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a long session lifetime is used, then usability is improved, but security deteriorates

Engineering Contradiction:
ImproveusabilityVSAvoidsecurity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback-driven session management system that continuously monitors user actions, device states, and contextual information throughout the session lifecycle. This feedback loop enables the system to assess risk dynamically and adjust session lifetimes accordingly, allowing long sessions to be maintained when user behavior and device characteristics indicate low risk, while automatically triggering reauthentication or session termination when suspicious patterns emerge, thus maintaining security without sacrificing usability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary risk assessments during session establishment and at periodic intervals throughout the session. By evaluating device trust levels, user behavior patterns, and contextual factors in advance, the system can proactively determine appropriate session lifetimes before security issues arise. This preliminary action enables the system to confidently extend session durations for trusted users and devices, improving usability while maintaining security through pre-emptive risk mitigation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3815331B1Adaptive session lifetime
Publication Date: 2023.03.08 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3815331B1 patent drawingFigure 1
  • EP3815331B1 patent drawingFigure 2
  • EP3815331B1 patent drawingFigure 3

AI summary

Session lifetime can be adapted based on session reputation. Session reputation can be computed based on sign-in risk and device risk, among other things. Session lifetime corresponds to a length of time a session is valid and can be determined automatically based on the session reputation. Subsequently, a token can be generated and returned in response to successful authentication that identifies a session and is valid for the determined lifetime.