Improving Shieh-Lin-Yang-Sun Signature Scheme

In 2000, Shieh et al. proposed a digital multi-signature scheme for authenticating the delegates of mobile code systems. Later, Hwang and Li showed that a forgery attack against the Shieh et al. scheme could be successful. Chang and Chang improved the Shieh et al. scheme. Their proposed scheme effectively defends against potential attacks as pointed out by Hwang-Li. Later, Zhang proved that the Chang-Chang version was still not secure. He showed that the other types of attacks could be successful. We therefore improve on the original Shieh et al. scheme so as to defend against strong attacks.