Entropy Pool Management for Virtual Machine Randomness

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Solution Overview

Problem

Virtual machines often experience reduced randomness and entropy in generated random numbers due to abstraction of hardware components, which can impact cryptographic processes and other computing scenarios.

Innovation Solution

A computing device architecture that generates and updates an entropy pool based on hardware components, with a virtual machine's entropy pool derived from the host operating system's pool, and uses a sequence counter to ensure randomness is maintained across cloning and usage, ensuring the entropy pool's integrity and randomness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a virtual machine abstracts hardware components, then the virtual machine can run on the computer, but the entropy of the generated numbers is reduced

Engineering Contradiction:
Improvevirtual machine compatibilityVSAvoidentropy quality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an intermediary mechanism that bridges the virtual machine's entropy pool and the physical hardware entropy sources. The host operating system acts as a mediator, capturing entropy from physical hardware components and transferring it to the guest operating system's entropy pool, thereby maintaining high-quality randomness despite the virtualization abstraction layer

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a nested entropy pool structure where the guest operating system's entropy pool is embedded within and derived from the host operating system's entropy pool. This nested arrangement allows the virtual machine to access entropy that originates from physical hardware while maintaining the hierarchical virtualization structure

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If entropy is weighted to improve entropy quality, then randomness quality improves, but the system complexity increases

Engineering Contradiction:
Improveentropy qualityVSAvoidentropy pool service architecture
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-service mechanisms where the host operating system automatically captures entropy from hardware components and makes it available to the guest operating system without requiring complex manual configuration or intervention. The entropy pooling process operates autonomously, reducing the burden on system administrators and simplifying the overall architecture

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2470989B1Entropy pools for virtual machines
Publication Date: 2018.01.10 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP2470989B1 patent drawingFigure 1
  • EP2470989B1 patent drawingFigure 2
  • EP2470989B1 patent drawingFigure 3

AI summary

In the host operating system of a computing device, entropy data is collected based at least in part on each of one or more hardware components of the computing device. An entropy pool is updated based at least in part on the collected entropy data, and data from the entropy pool is provided to a guest operating system running as a virtual machine of the computing device. The guest operating system maintains a guest operating system entropy pool based on the data from the entropy pool provided by the host operating system. The guest operating system accesses the guest operating system entropy pool and uses the guest operating system entropy pool as a basis for generating values including random numbers.