Charge Pump Current Scrambling for DPA Resistance
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Solution Overview
Problem
Conventional anti-pirating methods, such as constant current consumption masking, are insufficient to counter Differential Power Analysis (DPA) attacks, which can reveal the secret key of an encryption circuit by observing current variations during confidential operations in integrated circuits.
Innovation Solution
A method that activates a charge pump to generate significant current consumption fluctuations on the power supply line of an integrated circuit, causing current leakage during confidential operations, such as data reading and encryption code calculation, to mask these variations, using a switch whose state varies with data values in a register.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional constant current consumption masking is used, then current consumption variations are masked, but DPA analysis can still reveal secret key by observing current variations
Solution Approach 1:
The patent changes the parameter of current consumption by introducing a charge pump that generates significant current consumption fluctuations. This transforms the static masking approach into a dynamic one where the current consumption profile is actively modified through the charge pump's operation, making DPA analysis ineffective
Solution Approach 2:
The charge pump acts as an intermediary element between the power supply and the encryption circuit. It introduces current consumption fluctuations that mask the actual current variations caused by confidential operations, thereby protecting the secret key from DPA analysis without affecting the encryption circuit's functionality
2Object-affected harmful factors
If charge pump is activated to generate current consumption fluctuations, then current consumption peaks are masked, but device complexity increases
Solution Approach 1:
The charge pump is designed to serve multiple functions: it generates current consumption fluctuations for security protection, provides voltage boosting for memory operations, and can be integrated into existing power management structures. This multi-functionality reduces the overall device complexity by consolidating security and power management functions into a single component
3Reliability
If charge pump generates significant current consumption fluctuations, then security against DPA is enhanced, but energy consumption increases
Solution Approach 1:
The charge pump is activated periodically or in specific phases rather than continuously. It generates current consumption fluctuations during critical operations such as memory programming, erasing, and confidential data processing, while remaining inactive during other operations. This periodic activation reduces overall energy consumption while maintaining security protection when needed
Solution Approach 2:
The charge pump is activated in advance during memory programming and erasing operations to prepare the necessary voltage levels and current fluctuations. This preliminary action ensures that security protection is in place before confidential operations begin, while allowing the system to return to normal operation afterward, optimizing energy usage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively masks current consumption peaks associated with confidential operations, making it difficult for DPA analysis to determine the secret key, thereby enhancing the security of integrated circuits against DPA attacks.
Implementation Method 1
activation of a charge pump to generate current consumption fluctuations on the electric power supply line of the integrated circuit
Data Source
AI summary
A method for scrambling current consumption of an integrated circuit, at least during execution of a confidential operation by the integrated circuit that includes reading confidential data stored therein and/or the calculation of an encryption code is provided. The charge pump is activated to generate current consumption fluctuations on the electrical power supply line of the integrated circuit, at an intensity great enough to mask the current consumption variations associated with the execution of the confidential operation.