A Novel Security Analysis of ISRSAC Scheme

In 2017, Thangavel and Varalakshm proposed an article "Improved secure RSA cryptosystem for data confidentiality in cloud" which modified the RSA algorithm, as the ISRSAC scheme. In 2019, Liu and Hsu pointed out the ISRSAC scheme theoretical defect while r>3, then the α(n) may not be an integer. Liu et al. applied a little brute force attack (LBFA) to break the short key RSA algorithm. Based on Liu et al.'s idea, the authors applied LBFA to break ISRSAC, our research goal and methodology. There are 10 examples to describe the LBFA operation; examples 1 to 4 analyze the RSA algorithm, and examples 5 to 10 analyze the ISRSAC algorithm; these 8 examples provide strong evidence for our research result. The conclusion is drawn in the final section.