Secure-Enclave Data Processing With Sponge Duplex Obfuscation

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Solution Overview

Problem

Existing systems-on-chip (SOC) secure enclaves face challenges in providing robust encryption and authenticated encryption for data stored outside the enclave while maintaining performance and reducing hardware and software costs, particularly against side-channel and fault attacks.

Innovation Solution

A computer-implemented method using a cryptographic function with a sponge duplex construction that applies obfuscation functions to input data before processing, ensuring secure encryption and decryption by introducing an additional layer of security against side-channel attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If AES-based encryption is used in secure enclaves, then security robustness is improved, but hardware cost and complexity increase

Engineering Contradiction:
Improvesecurity robustnessVSAvoidhardware cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a simplified cryptographic function that copies the essential security properties of AES through a sponge duplex construction, achieving comparable security robustness against side-channel and fault attacks without requiring the full AES hardware implementation. This reduces hardware gate count while maintaining security equivalence.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent employs lightweight cryptographic primitives and a streamlined sponge function design that uses fewer hardware resources compared to AES. The simplified construction achieves adequate security for the specific secure enclave application without the overhead of implementing the complete AES standard, thereby reducing hardware cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If AES-based encryption is used in secure enclaves, then security robustness is improved, but performance deteriorates

Engineering Contradiction:
Improvesecurity robustnessVSAvoidperformance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The sponge duplex construction replicates the security functionality of AES with a more performance-efficient architecture. By using a simplified permutation function and optimized state management, the patent achieves comparable security outcomes with faster execution speed and lower computational overhead.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent adjusts cryptographic parameters such as the sponge function rate and capacity, and the number of rounds, to optimize performance for the specific secure enclave application. These parameter optimizations enable faster encryption operations while maintaining robust security against side-channel and fault attacks.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If obfuscation functions are applied to input data, then security against side-channel attacks is improved, but device complexity increases

Engineering Contradiction:
Improvesecurity against side-channel attacksVSAvoidsoftware code
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces obfuscation functions as intermediary layers between the input data and the sponge duplex construction. These obfuscation functions mask the true data values and operation patterns, preventing side-channel attackers from extracting sensitive information through power analysis or timing attacks, while the overall system complexity remains manageable.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4641420A1Processing of data in a secure environment
Publication Date: 2025.10.29 NAGRAVISION SRL
  • EP4641420A1 patent drawingFigure 1
  • EP4641420A1 patent drawingFigure 2A~2B
  • EP4641420A1 patent drawingFigure 3

AI summary

A computer-implemented method, executed within a secure environment, comprises: receiving input data comprising a message, the message comprising N message portions, where N is greater than or equal to 1; initializing a cryptographic function by retrieving, selecting or generating initial state data, the cryptographic function comprising a message processing phase (MPP); applying a first stage of the MPP of the cryptographic function, wherein applying the first stage of the MPP of the cryptographic function comprises: applying a first MPP obfuscation function to a first MPP obfuscation function input to generate a first obfuscated MPP input, the first MPP obfuscation input derived from a received message portion; and applying a first MPP function to a first MPP function input derived from the first obfuscated MPP input and the initial state data of the encryption function to generate a first MPP output.