M.Tech

Computer Science Engineering is a great course to graduate from, Firstly, you could take up a job or some kind of project experience to get hands on and a recollection of what you have studied and what is trending now most importantly. Check how working in this field itself suits you. You could do more certificate courses- free and paid in the field of testing, designing, programming, analytics. But for that get a thorough idea through online reading and communicating with people working already, and putting yourself through project experience first. Only when you are clear you can go on with working in area, specialise in it through short term course or even Masters as the need may be, If altogether you prefer to be in Management, then even an MBA is a good option. Again, under MBA study categories, choose the right area based on your skill set, abilities and interest and your expectation of outcome.

MTech Cryptography is a brand new course which ISI introduced this year. There is a new centre opened at ISI called RC Bose Institute of Cryptography which will be running this particular course at ISI. But in the subsequent years this course will be highly demanding.
May be the admission in these years will be easy but I can assure you if you can successfully complete the course with decent marks, you will surely be getting a job of an average lpa of 15 lakh and as well as PhD in Indian Institutes as well as universities in the USA.
RC Bose faculties at ISI have good connections in abroad so placements and PhD options wont be a problem in my view.