Chandrasekaran, ArulKumaran. “Secure Cryptographic Communication Using Ultrasound Audio for Frictionless Payment Transactions and Secure Conversations over a Short-Range Human audible/Inaudible Spectrum”. International Journal of Scientific Reports 9, no. 8 (July 7, 2023): 248–250. Accessed September 26, 2025. https://www.sci-rep.com/index.php/scirep/article/view/1246.