Comment on novel public key encryption technique based on multiple chaotic systems

Recently, a novel public key edcryption technique based on multiple chaotic systems has been proposed. The scheme employs m-chaotic systmes and a set of linear functions for key exchange over an insecure channel. The security of the proposed algorithm grows as NPm, where M, P are the size of the key and the computational commplexity fo the linear functions respectively. In this paper, the fundamental weakness of the cryptosystme is pointed out and a successful attack is described. Given the public keys and initial vector, one can calculate the secret key based on Parsevala's theorem. Both theoretical and experimental results show that the attacker can access to the secret key without difficulty. The lack of security discourages the use of such algorithm for practical application.