There are comments flying around as to whether cryptography should be approached as a science or as engineering. It apparently started on Twitter. Bruce Schneier has weighed in and linked to an interesting essay by Colin Percival.
The actual border lands might not be surveyed yet, but I believe there's a distinct field of cryptographic engineering, just as computer architecture can be independent of circuit design. In both cases we try to establish design rules so that engineers can build things with predictable properties. In both cases we can push the envelope of those rules and yield disaster.
We establish an engineering discipline by trying to codify the design rules, teach them, build with them, and assess the results. That's what we see in security/cryptographic engineering these days. It's healthy even though we end up with occasional vulnerabilities.