Efficient modified RC5 based on chaos adapted to image encryption

摘要

RC5 is a well-known block cipher notable for its simplic-nity, speed, suitability for hardware and software implementation, andnits low memory requirement. However, RC5 can be broken with vari-nous attacks, revealing weak security. This is mainly due to the poorndiffusion operation that allows the cipher to be attacked with lessncomplexity than that of the exhaustive search. In this work, wenmodify the RC5 to give high level security, and adopt it for imagenencryption by adjusting the structure of both the encryption routinenand the key schedule. We generate round keys based on chaos.nThen, we strengthen the diffusion operation by making heavy use ofnrotations. The security analysis of the modified cipher against sev-neral attacks is explored from a strict cryptographic viewpoint. Experi-nmental results demonstrate that the modified RC5 provides an effi-ncient and secure way for image encryption.