@ARTICLE{Li:Cryptanalysis:PLA2007, author = {Chengqing Li and Shujun Li and Gonzalo Alvarez and Guanrong Chen and Kwok-Tung Lo}, title = {Cryptanalysis of two chaotic encryption schemes based on circular bit shift and {XOR} operations}, journal = {Physics Letters A}, year = {2007}, volume = {369}, number = {1-2}, pages = {23-30}, doi = {10.1016/j.physleta.2007.04.023}, note = {preprint available online at \url{http://www.hooklee.com/pub.html}}, }