Cryptographic IC Power Waveform Masking Against Power Analysis

Solution Overview

Problem

Existing encryption methods for programmable logic circuits are vulnerable to power analysis attacks, where attackers can determine the decryption key by monitoring power consumption variations, compromising the security of the encrypted design.

Innovation Solution

A secure cryptographic device is implemented with a power supply interface, a cryptographic processing block, a random number generator, and a complex multiplication circuit that modulates the power variation waveform, making it difficult for attackers to identify key-dependent operations through complex statistical analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard encryption algorithms (DES, AES) or one-time pad are used to encrypt the configuration bitstream, then the design is protected from unauthorized copying during transmission, but the decryption key stored in the programmable IC becomes vulnerable to power analysis attacks

Engineering Contradiction:

Improvesecurity of encrypted designVSAvoidvulnerability to power analysis attacks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-generating random masks and preparing masking circuits before the decryption operation. The random masks are generated and stored in advance, and the masking logic is pre-configured to combine with the decryption output, so that when power analysis occurs during decryption, the key is already protected by the pre-applied masking operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses random masks as intermediaries between the decryption key and the final decrypted output. The masking operation acts as a mediator that prevents direct correlation between power consumption patterns and the decryption key, making it difficult for attackers to extract the key through power analysis while still allowing legitimate decryption to proceed

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the decryption key is stored in nonvolatile memory of the programmable IC, then the bitstream can be decrypted within the device to prevent reading during loading, but the stored key becomes a target for attackers attempting to obtain it through various attack modes

Engineering Contradiction:

Improveprotection during bitstream loadingVSAvoidexposure to key extraction attacks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-generating random masks and preparing masking circuits before the decryption operation. The random masks are generated and stored in advance, and the masking logic is pre-configured to combine with the decryption output, so that when power analysis occurs during decryption, the key is already protected by the pre-applied masking operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses random masks as intermediaries between the decryption key and the final decrypted output. The masking operation acts as a mediator that prevents direct correlation between power consumption patterns and the decryption key, making it difficult for attackers to extract the key through power analysis while still allowing legitimate decryption to proceed

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8522052B1Method and integrated circuit for secure encryption and decryption

Publication Date: 2013.08.27 XILINX INC

AI summary

In one embodiment of the present invention a secure cryptographic device is provided. The device includes a power supply interface, a cryptographic processing block coupled to the power supply interface, a random number generator, and a complex multiplication circuit. The complex multiplication circuit has an output coupled to the power supply interface for modulating a power variation waveform detectable on the power supply interface. The complex multiplication circuit also has a first input coupled to an output of the random number generator and a second input coupled to the power supply interface.