Ngwe, T. T., and S. W. Phyo. “Digital Envelope System Based on Optimized NTRU (Number Theory Research Unit) and RC6 Algorithm”. International Journal of Computer (IJC), vol. 19, no. 1, Oct. 2015, pp. 67-78, https://ijcjournal.org/index.php/InternationalJournalOfComputer/article/view/455.