Authentication Tag Computation Protection Against Side-Channel Attacks

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Solution Overview

Problem

Existing cryptographic systems, such as AES-GCM, are vulnerable to side-channel attacks that can reveal the secret authentication key, allowing attackers to alter data and authentication tags, compromising encryption security.

Innovation Solution

Implementing countermeasures like data randomization, multiplexing, and circuit optimization to prevent power and electromagnetic side-channel attacks during authentication tag computation, including the use of pseudo-random number generators and multiplexers to obscure intermediate results and reduce leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If AES-GCM encryption operation is implemented without additional protection, then encryption functionality is provided, but the authentication key is vulnerable to side-channel attacks

Engineering Contradiction:
Improveauthentication key securityVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The authentication tag computation is divided into multiple shares, where each share is computed separately and then combined. This segmentation prevents side-channel attacks from directly observing the complete authentication key, as the key is split across multiple computational paths that are individually protected.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiplexers are introduced as intermediary components that control the flow of data between different computational paths. These multiplexers act as mediators that prevent direct observation of intermediate results containing authentication key information, while still allowing the computation to proceed correctly through controlled signal routing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If data randomization and multiplexing are implemented, then side-channel attack resistance is improved, but circuit complexity increases

Engineering Contradiction:
Improveside-channel attack vulnerabilityVSAvoidcircuit structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The circuit employs dynamic multiplexing where the selection of computational paths changes based on control signals. This dynamic behavior ensures that the same authentication key material is processed through different paths in different clock cycles, preventing attackers from correlating power consumption patterns with specific key values across multiple observations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The implementation changes the temporal parameters of computation by distributing the authentication tag calculation across multiple clock cycles rather than completing it in a single operation. This temporal distribution, combined with multiplexing, alters the power consumption profile over time, making it difficult for attackers to extract key information through traditional DPA methods.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If authentication tag computation is protected against side-channel attacks, then security is enhanced, but computation time increases

Engineering Contradiction:
Improvecryptographic securityVSAvoidcomputation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The protected authentication tag computation maintains continuous useful action by overlapping the protected computation with other operations. The multiplexed structure allows different shares of the authentication tag to be computed in parallel during different time slots, ensuring that the overall computation completes efficiently while maintaining continuous protected operation throughout the process.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3972187A1Protection of authentication tag computation against power and electromagnetic side-channel attacks
Publication Date: 2022.03.23 INTEL CORP
  • EP3972187A1 patent drawingFigure 1A~1B
  • EP3972187A1 patent drawingFigure 2A
  • EP3972187A1 patent drawingFigure 2B

AI summary

Protection of authentication tag computation against power and electromagnetic side-channel attacks is described. An example of one or more storage mediums includes instructions for performing a process for calculation of an authentication tag for a data encryption operation, including generating one or more random values; receiving multiple data blocks for calculation, and performing calculation utilizing the received data blocks and the one or more random values to generate intermediate values; performing a data accumulation operation to accumulate random values in calculation of the data blocks; and calculating the authentication tag based at least in part on the generated intermediate values and the accumulated random values.