, B. Y. R. S. Introducing Three Tier Captcha to Prevent DDOS Attack in Cloud Computing. International Journal on Recent and Innovation Trends in Computing and Communication, [S. l.], v. 2, n. 7, p. 1969–1973, 2014. DOI: 10.17762/ijritcc.v2i7.3440. Disponível em: https://ijritcc.org/index.php/ijritcc/article/view/3440. Acesso em: 28 jul. 2024.