Zhiping Wu Dingfeng Ye Weiju Ma Perturbed Variant of TTM Cryptosystem. 2082-2087 2006 43 Journal of Computer Research and Development 12 http://WWW.CQVIP.COM/QK/94913X/200612/23426046.html db/journals/jcrd/jcrd43.html#WuYM06