Dishonest Hardware Policies for Side Channel Attack Prevention

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Solution Overview

Problem

Conventional computer systems are vulnerable to side channel attacks, where attackers can infer sensitive information by analyzing access permission and timing information, and existing protection methods like encryption are power-consuming and expensive.

Innovation Solution

Implementing 'dishonest' hardware policies that manipulate access permission bits in page tables to deny attackers information about protected memory locations, using dishonest policy bits to return false or random data instead of actual contents, thus preventing side channel attacks without the need for expensive encryption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encryption is used to protect memory contents, then security against side channel attacks is improved, but power consumption increases significantly

Engineering Contradiction:

ImprovesecurityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of protecting memory by encrypting data and allowing legitimate access, the patent inverts the approach by deliberately providing false protection information to attackers. The system sets dishonest permission bits in page tables that make protected regions appear accessible when they are not, thereby preventing side channel attacks without requiring encryption or exception handling.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If encryption is used to protect memory contents, then security against side channel attacks is improved, but implementation cost increases

Engineering Contradiction:

ImprovesecurityVSAvoidimplementation cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses existing permission bit structures in page tables and repurposes them for dishonest protection. Instead of creating a completely new encryption hardware system, it copies and modifies the existing permission bit mechanism to provide security through deception, thereby reducing implementation complexity and cost.

Inventive Principle:

Principle #26Copying

3Ease of operation

If access permission information is provided to attackers, then ease of operation is improved, but vulnerability to side channel attacks increases

Engineering Contradiction:

Improveaccess permissionVSAvoidside channel attack vulnerability

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of permission information leakage into a beneficial security feature. By intentionally providing false permission information through dishonest permission bits, the system causes attackers to draw incorrect conclusions about memory protection, thereby preventing side channel attacks while maintaining normal system operation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS8935775B2Method and apparatus for dishonest hardware policies

Publication Date: 2015.01.13 INTEL CORP

AI summary

A system implements dishonest policies for managing unauthorized access requests. The system includes memory management hardware to store a set of dishonest policy bits, each dishonest policy bit that is configured to a predetermined value indicating disallowed access for one of a set of memory ranges. When a processor receives an access request for a location in a memory range to which access is not allowed as indicated by a set dishonest policy bit, the processor returns a false indication according to a dishonest policy that the requested access has been performed.