Lightweight Cryptography for Medical Image privacy on Resource constraint hardware

Abstract In the current digital landscape, protecting medical images during transmission is crucial for maintaining patient confidentiality and ensuring the integrity of sensitive data. Lightweight cryptographic methods offer an efficient and practical approach for secure communication in environments with limited computational resources. This work introduces a lightweight encryption framework specifically designed for medical image protection on a Cyclone IV FPGA, optimized for processing 256×256 DICOM images with 8-bit pixel depth, in line with medical imaging standards. The architecture integrates a Linear Feedback Shift Register (LFSR) to achieve confusion and a three-dimensional Henon map for effective diffusion, while Cipher Block Chaining (CBC) mode further enhances security. The proposed system demonstrates strong encryption performance with low hardware overhead, utilizing only 1984 logic elements and dissipating 131.24mW of power. The encrypted images achieve high randomness with an entropy value of 7.99908 and exhibit strong resistance to visual analysis with a PSNR of less than 6dB. Security validation through statistical and Chosen Plain Text Attack analysis, along with randomness verification using the NIST SP 800-22 test suite, confirms the cryptographic robustness and practical suitability of the design for real-time medical image protection.