If anyone is interested in pursuing database and/or line encryption, a
very useful library is LibTomCrypt. While not actively supported, it's
been stable for about a decode, and has a very open style BSD license.
The library has just about everything you'd ever want, but I've been
content with SHA, AES, and RSA. The code is C, but the conversion to
C++ is trivial. Like most crypto libraries, you have to argue with it a
bit to subset, but unlike others, it's possible.

But a small warning is in order: Like virtually everything in the crypto
world, things are more complicated than need be.

--
Jim Starkey
Founder, NimbusDB, Inc.
978 526-1376