MATLAB Implementation of MD5 Hash Function with Algorithmic Details

The following presents a MATLAB simulation implementation of the MD5 hash function for learning and technical exchange. Hash functions are algorithms that compress messages of arbitrary length into fixed-length outputs, commonly used in encryption, digital signatures, and data integrity verification. MD5 is a widely adopted hash function producing a 128-bit output. The implementation involves key algorithmic stages including message padding, initialization of four 32-bit buffers (A, B, C, D), and processing of 512-bit message blocks through 64 rounds of bit-level operations. In MATLAB, this is achieved using loops for block processing, bitwise operations (AND, OR, XOR, NOT), and modular arithmetic for circular shifts. The core algorithm utilizes four non-linear functions (F, G, H, I) and a precomputed sine-based constant table for each round. Key implementation aspects include: - Padding the input message to ensure its length is congruent to 448 modulo 512 - Appending the original message length as a 64-bit integer - Processing blocks through four rounds of 16 operations each, employing different permutations and constants - Combining buffers through additive operations after each block processing This simulation helps understand hash function mechanics, including collision resistance properties and applications in cybersecurity. The code demonstrates practical bit manipulation techniques in MATLAB, using uint32 data types for efficient bit-level computations and typecasting for proper byte ordering. Through this implementation, learners can deepen their understanding of cryptographic principles and MATLAB's capabilities for low-level algorithm development.