Hello aspirant,

First you have to complete your BTech in computer science brance .

First teach yourself about security, mainly web security, reverse engineering, cryptography and networking. Choose an area of your like and learn new things and sharpen your skill in that particular field.

The best way to do this is to play CTF (Capture the Flag) competition, it's an online hacking competitions that can be played online. People around the world compete each other. You can find upcoming capture the flag competitions from here.

Each CTF will of different difficulty or rating, choose the ones with the low rating. Also there are practice CTF that are available around the clock you can find the list here.

In the beginning it will be tough to crack the puzzles but be steady and keep trying.

Once you start to solve the challenges start a blog and post how you solved the challenges, put it up in resume and apply for security jobs in corporates, they won't ignore you, your blog will speak for you.

Goodluck!