Decryption Method Preventing Timing and DFA Attacks
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Solution Overview
Problem
Existing methods for determining plaintext from a cipher, such as the RSA method, are vulnerable to timing attacks and differential fault analysis (DFA) attacks, which can compromise the security of the secret key, requiring significant computational effort to prevent these attacks.
Innovation Solution
A method that determines the plaintext using a secret key in binary form, where each bit of the secret key is processed in parallel with a security variable, and a verification variable is calculated using an exponent compatible with the secret key, employing 'always multiplication and squaring' or 'always addition and doubling' algorithms to maintain consistent processing time and verify calculations against disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RSA decryption methods are used, then decryption functionality is achieved, but the system becomes vulnerable to timing attacks and DFA attacks
Solution Approach 1:
The patent introduces a verification calculation that is performed in parallel with the main decryption calculation before the final result is produced. This preliminary verification action detects potential attacks (timing attacks and DFA attacks) before they can compromise the secret key, thereby preventing the harmful effects while maintaining decryption functionality
Solution Approach 2:
The patent implements a feedback mechanism where the result of the verification calculation is used to validate the main decryption result. If the verification fails (indicating a potential attack), the system can detect and respond to the attack, providing feedback that enhances security without preventing the decryption operation itself
2Reliability
If verification methods are added to prevent attacks, then security is improved, but computational effort increases significantly
Solution Approach 1:
The patent performs a verification calculation that processes only part of the data (using a reduced exponent) rather than the complete decryption operation. This partial action provides sufficient security verification while consuming significantly less computational resources than performing a full verification decryption
Solution Approach 2:
The verification calculation is performed in parallel with the main decryption, using preliminary computation with a reduced exponent. This approach establishes security verification early in the process without adding significant sequential computational overhead to the main decryption operation
Data Source
AI summary
The invention relates to a method of determining a plaintext M on the basis of a cipher C and using a secret key d, wherein the secret key d is used in binary form, wherein the plaintext M is determined in each iteration step i for the corresponding bit di and a security variable Mn is determined in parallel therewith, and then a verification variable x is determined by means of a bit-compatible exponent of the secret key d.