If you want to do cryptography, it's probably easiest to get into it through an academic career. Please understand it's quite a small field where the amount of talkers largely exceeds contributors. Alternatively, start learning and contributing to open source crypto libraries and projects, you'll meet people who can help you.

It's funny you can't find application security job postings, most of the bread and butter work these days is web, mobile and penetration testing. Get into security consulting and you'll do this type of gigs till your fingers bleed.

I'd suggest you learn about security, there's plenty of good info and books to be found and try to apply it instead of talk about it.

Good luck.