I'm glad it's a good library. I was responding especially to "Make an arbitrary scheme on top of" whatever underpinnings one might choose, good or bad. That's not something we amateurs should ad lib where security matters.

We will undoubtedly have to integrate and access libraries like NaCl. But we should do so in keeping with best practices recommended by cryptographers (e.g. through NaCl's documentation), not by layering an arbitrary scheme on top.