Secure Hash Function Design Using Bijective Pre-Processing and CBC Mode
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Solution Overview
Problem
Current cryptographic hash functions, such as MD5 and SHA-1, are vulnerable to collision attacks, compromising their security and collision resistance, necessitating the development of a more robust and secure hash function to prevent hash collisions.
Innovation Solution
A secure hash algorithm combining message pre-processing techniques, including bijective operations like Shuffling, T-function, and Linear Feedback Shift Register (LFSR), with Cipher Block Chaining (CBC) mode, to produce a fixed-size output, enhancing collision resistance and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hash functions (MD5, SHA-1) are used, then computational efficiency and simplicity are maintained, but collision resistance deteriorates
Solution Approach 1:
The hash function is divided into multiple independent rounds (e.g., 64 rounds for SHA-512), each performing specific bitwise operations, logical functions, and modular additions. This segmentation allows each round to contribute to diffusion and confusion while maintaining overall computational efficiency.
Solution Approach 2:
The patent implements nested iterative structures where multiple rounds are nested within each other, and each round contains nested operations (logical functions nested within bitwise operations nested within modular additions). This nested structure enhances security through repeated transformation while organizing complexity in a manageable hierarchy.
2Reliability
If hash function security is strengthened through multiple rounds and operations, then collision resistance improves, but computational complexity increases
Solution Approach 1:
The patent provides multiple hash function variants (SHA-224, SHA-256, SHA-384, SHA-512) with different output lengths and round counts. Users can select parameters based on security requirements versus computational constraints, allowing optimization of the security-computation tradeoff for specific applications.
Solution Approach 2:
The patent implements a fixed number of rounds (e.g., 64 rounds for SHA-512) that exceeds the theoretical minimum required for security. This excessive action provides a security margin against future cryptanalytic advances while maintaining reasonable computational efficiency.
3Reliability
If message pre-processing is applied to reduce collisions, then hash collision resistance improves, but processing time increases
Solution Approach 1:
The patent incorporates message scheduling and pre-computation of message blocks into the hash function structure itself. The input message is pre-processed into scheduled arrays of words before the main compression function executes, distributing the preprocessing workload efficiently across the computational pipeline.
Data Source
AI summary
A system and method for designing a secure hash function is provided. Both of which have been designed for secure hash functionality, Secure Hash Algorithm (SHA-3) using pre processing (MP) methods and to help reduce hash collisions. It is a one way hash function which is a combination of message pre-processing which is a bijective function and the cipher block chaining mode (CBC).