Abstract
<title>Abstract</title> <p>This study introduces the Hybrid Split-Based Chaotic Cryptosystem (HSBCC), a unified encryption framework designed to secure arbitrary binary files through the integration of a dynamically generated Unimodular Hill Cipher, Logistic Map-based chaotic key generation, Shift Cipher 128, AES-based session key protection, and Elliptic Curve Cryptography (ECC). The proposed architecture adopts a split-based encryption mechanism that divides plaintext into a primary segment encrypted using a dynamically reconstructed unimodular Hill Cipher and a secondary segment protected with Shift Cipher 128. This strategy removes the need for padding while preserving the original file size and format. The encryption matrix is deterministically reconstructed from user passwords using a Logistic Map with a control parameter of r = 3.923, ensuring high key sensitivity, reproducibility, and guaranteed matrix invertibility through unimodular matrix generation. Performance evaluation was conducted using benchmark images, medical images, PDF documents, and various binary files to assess both security and functionality. Experimental results indicate that the proposed cryptosystem achieves ciphertext entropy values approaching the theoretical maximum, produces nearly zero adjacent-pixel correlations, exhibits strong avalanche characteristics, and generates highly uniform ciphertext distributions. Integrity verification demonstrates perfect lossless decryption, with all recovered files producing MD5 hashes identical to their original counterparts. Additional experiments using an 815,491-byte PDF document and matrix dimensions of 8, 88, and 888 further confirm deterministic key reconstruction, ciphertext uniqueness, file-size preservation, and complete plaintext recovery. Scalability analysis reveals moderate computational overhead while maintaining practical encryption performance across different matrix dimensions. Overall, the findings demonstrate that HSBCC provides a secure, scalable, and flexible cryptographic framework capable of protecting arbitrary binary data with strong cryptographic robustness, deterministic key generation, and complete preservation of file integrity and format.</p>