l-1j-cho said:
I am interested in cryptography. I am seriously considering to apply for mathematics and computer science double major. However, are cryptographers in demand? I am quite sure that ordinary people have not heard of such occupation at all.
I think this is a good choice - more and more applications are using cryptography and digital certificates for authentication. I am a physicist and mainly concerned with implementing public key infrastructures and doing security consulting with a focus on cryptography. During the last years I have seen an increasing demand for people with such skills.
Make sure that you acquire also some not-too-theoretical skills such as implementing cryptography in applications, e.g. learn how to use cryptographic algorithms in Java or .NET or some other popular language or how to implement systems managing networking security (e.g. plan and design authentication based on IPsec, 802.1x to secure wired or wireless networks).
You might be employed at the IT department of large corporations or agencies - as a developer that e.g. builds some custom authentication client, or as a security architect. You could also work for hardware or software vendors that develop for example smartcards, biometric devices etc. Or you would work for a company that specializes in security consulting and thus evaluate security solutions.
You might become or remain a technical specialist, e.g. a security researcher and 'reverse engineer' and test other products. Many security experts turn to more general aspects later in their career, such as compliance or security awareness - it is up to you. (I personally prefer the hacker-like aspects actually.)
I would try to get in touch with potential employer companies during studying, e.g. you might need some test hardware or software to work on a project - that might be a good chance to talk to the development teams at the vendor companies.
If you are interested in cryptography, I would read the blog of security guru Bruce Schneier:
http://www.schneier.com
This should give you an overview about a variety of topics security experts and cryptographers work on.
So in summary cryptography is a promising field that gives you several career options.
) but something - rather than just math, the math of nothing. This means taking some courses in those things, studying them in their own terms. I guess it will make you more eventually employable, and without it you may be handicapped in interacting professionally with those of another discipline. If that means a few less courses on the pure math of some specialised nothing what does it matter? You'll never get on top of the whole lot anyway. Once you have picked up good habits, a reasonable background and practice, you can always mug up a bit more math of any particular subspeciality of the math of nothing as and when you need it. Or even be free to devote your life to it after all. One more course will be a drop in the vast ocean of the math of nothing anyway.