The certificate of Ehical hacking is a qualification obtained by assessing the security of computer systems, using penetration testing techniques.Penetration tests are employed by organizations that hire certified ethical hackers to penetrate networks and computer systems with the purpose of finding and fixing security vulnerabilities.
You can refer book for Certificate in Ethical Hacking by Indian Author. Book Name-The Unofficial Guide to Ethical Hacking Author Name-by Ankit Fadia Price-Rs.350 (approximately) Link : http://www.amazon.in/Unofficial-Guide-Ethical-Hacking/dp/1403929645?tag=googinhydr18418-21&tag=googinkenshoo-21&ascsubtag=fd802556-af93-46d2-85f1-95599dffa27b