Equivalent of Data Protection API on Linux

Question

Microsoft Windows 2000 and later versions expose the Data Protection API (DPAPI) that encrypts data for a per-user or per-system context. The caller does not provide a key with

Answer 1

It doesn't look any more (or less) advanced than PGP, or Pretty Good Privacy. There are APIs available for PGP, and the one that I recall others speaking kindly of is Bouncy Castle.

Here's an example of how someone used Bouncy Castle.

Better APIs or solutions may be available, depending on your specific needs.