It all depends on what suits you best. Technical positions command good salaries. If you get training in a security tool that's in demand, you'll soon have plenty of companies competing for your services. If you're a mainframe engineer, try mainframe security administration products like IBM's Resource Access Control Facility. There are quite a few products that seem to be in demand at the moment.
Firewalls are a case in point.
Most companies have a firewall, and Check Point has a very large market share. It's also one of the easiest to use, which is more than just a coincidence. Cryptography projects, in general, are always difficult to staff because few people know much about cryptography. But in the long run, you'll do best with a professional qualification, such as a Certified Information Systems Security Professional or Certified Information Systems Auditor certification. You can learn security technologies and mechanisms quite easily, but there's a required mind-set that you can't learn no matter how hard you try.