Security and Performance Analysis of a Hybrid Key Generation Method Combining DES and RSA with Random Rotations

Abstract

This paper presents a hybrid method for generating encryption keys by combining DES and RSA algorithms with the application of a random rotation matrix in the key generation stage. The aim is to enhance the difficulty of key derivation while maintaining performance.  We conducted a formal security analysis under the IND-CPA model and performed five repeated experiments to measure key-generation time, encryption time, and decryption time for 1 MB messages on a test platform equipped with an Intel Core i7 processor and 16 GB of RAM. The results showed that the key generation time of the proposed method was 0.50 ms compared to 0.40 ms for the conventional method (a 25% increase). —matching the performance of the traditional RSA+AES scheme—while encryption time decreased by 20% to 1.20 ms and decryption time decreased by 18% to 1.30 ms compared to the RSA+AES approach. The research indicates that integrating random rotations effectively increases the complexity of the final key without imposing a significant performance overhead, rendering the method suitable for high-security environments such as Internet of Things networks and enterprise systems.