Homomorphic Encryption for White Box Cryptography Memory Reduction
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Solution Overview
Problem
Conventional white box cryptography methods in insecure environments are memory-intensive due to the use of numerous correspondence tables, which is inefficient for cryptographic processing.
Innovation Solution
A cryptographic processing method that uses homomorphic encryption functions to transform input bytes into output bytes through Boolean logic operations, reducing the number of look-up tables required by applying operations to intermediate cryptograms and determining bits using inverse functions, thereby minimizing additional manipulations and memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional white box cryptography methods use numerous lookup tables to secure cryptographic processing, then security is improved, but memory consumption increases significantly
Solution Approach 1:
The patent changes the fundamental parameter of cryptographic operation from table-lookup-based to homomorphic encryption-based. By applying homomorphic encryption functions to input words and performing operations on intermediate cryptograms, the system achieves the same security objectives without requiring numerous lookup tables, thus reducing memory consumption while maintaining security
Solution Approach 2:
The patent replaces the mechanical system of lookup tables (memory access operations) with a mathematical system based on homomorphic encryption functions. Instead of retrieving pre-computed values from tables, the system performs algebraic operations on encrypted data, substituting memory-intensive operations with computation-efficient cryptographic transformations
2Ease of manufacture
If conventional methods use numerous lookup tables for cryptographic operations, then cryptographic processing is achieved, but device complexity increases
Solution Approach 1:
The homomorphic encryption function serves multiple purposes: it encrypts input data, enables intermediate computations on encrypted values, and maintains security throughout the processing chain. This single mathematical function replaces numerous specialized lookup tables, each designed for specific cryptographic operations, thereby reducing overall system complexity while maintaining full cryptographic functionality
Solution Approach 2:
The patent merges multiple separate cryptographic operations that would traditionally require distinct lookup tables into a unified homomorphic encryption framework. By combining encryption, computation, and transformation operations into a single mathematical system, the patent reduces device complexity while preserving cryptographic processing capabilities
Data Source
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AI summary
A cryptographic processing method transforming an input multiplet into an output multiplet comprises the following steps: - conversion of a plurality of words, each comprising at least one bit of the input multiplet, into input cryptograms by applying, to each of said words, a homomorphic encryption function from a first group to a second group equipped with an operation; - obtaining output cryptograms as a function of the input cryptograms, this obtaining step including at least one processing during which said operation is applied to two intermediate cryptograms, this processing producing a cryptogram image by the homomorphic encryption function of a word including a Boolean logical combination of two bits included respectively in two antecedent words, for the homomorphic encryption function, of said two intermediate cryptograms;- Determination of bits of the output multiplet by applying to the output cryptograms respectively an inverse function of the homomorphic encryption function. An associated electronic device and computer program are also provided.