RSA Decryption Circuit with Concurrent False Operations
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Solution Overview
Problem
RSA decryption devices are vulnerable to sideband attacks where attackers can measure signals to determine the operations performed, allowing them to acquire the RSA private key used for decryption.
Innovation Solution
The decryption method and device perform a combination of multiplication and square operations using an RSA private key, incorporating false operations that are concurrent with the actual operations, making it difficult for attackers to identify the private key from signal measurements by introducing first and second false operations that do not affect the decrypted data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard RSA decryption operations are performed, then decryption functionality is achieved, but the device becomes vulnerable to sideband attacks that can reveal the private key
Solution Approach 1:
The patent applies preliminary action by pre-generating multiple false operation sequences (both square operations and multiplication operations) before the actual decryption process. These false sequences are prepared in advance and then executed concurrently with the real decryption operations, creating a mask that prevents attackers from distinguishing genuine operations from fake ones through sideband analysis.
Solution Approach 2:
The patent merges genuine decryption operations with false operations into a single concurrent execution process. By combining real square operations with false square operations and real multiplication operations with false multiplication operations simultaneously, the system creates an indistinguishable operational pattern that protects the private key while maintaining decryption functionality.
2Reliability
If false operations are introduced to protect against sideband attacks, then security is improved, but the number of operations and processing time increase
Solution Approach 1:
The patent maintains continuity of useful action by executing false operations concurrently with genuine decryption operations rather than sequentially. The false square operations run simultaneously with real square operations, and false multiplication operations run simultaneously with real multiplication operations, ensuring that the protective measure does not add temporal overhead to the decryption process.
Solution Approach 2:
By pre-generating and preparing the false operation sequences in advance, the system eliminates the need for additional processing time during the actual decryption. The false operations are ready to be executed concurrently from the start, preventing any time loss while maintaining security.
3Reliability
If concurrent square and multiplication operations are performed, then operational masking is achieved, but the device requires more complex circuitry to handle simultaneous operations
Solution Approach 1:
The patent segments the decryption operations into distinct functional units: a squarer for square operations, a multiplier for multiplication operations, and a multiplexer for selecting between them. Each component handles a specific type of operation independently, and the multiplexer coordinates their outputs based on the private key bits, allowing concurrent execution without requiring a completely redesigned complex circuit.
Solution Approach 2:
The multiplexer serves multiple functions: it selects between the output of the squarer and the output of the multiplier based on the current bit of the private key, and it also coordinates the execution of false operations. This multi-functional component reduces the need for separate control circuits, thereby managing device complexity while enabling concurrent operational masking.
Data Source
AI summary
A decryption method includes receiving encrypted data, in which the encrypted data is encrypted by an RSA public key; and performing at least one multiplication operation and at least one square operation according to an RSA private key and the encrypted data to acquire decrypted data. A false square operation is performed in performing one of the at least one multiplication operation, or a false multiplication operation is performed in performing one of the at least one square operation.