A Variable-Sized Chaotic Block Encryption Algorithm Based on Spatiotemporal Chaotic Map and IDEA

Both conventional and chaotic cryptography have advantages and disadvantages. If their advantages are combined effectively, security of a cryptosystem based on conventional and chaotic ciphers can be greatly enhanced. Inspired by this, we proposed a variable-sized block encryption algorithm, GCID, by virtue of spatiotemporal chaotic map and IDEA block encryption scheme. Being of unfixed block size and large key space, GCID cipher is unpredictable. Besides, it is uniformly distributed and highly sensitive to tiny change of plaintext and key. Numerical tests and theoretical analyses indicate that the algorithm is secure against brute-force attacks, statistical attacks and differential attacks.