I know of no direct support. Failing that, you could just write some kind of filter to do this work for you. It wouldn't be difficult. Consider making a DBD::db driver that just proxies for some other kind of database. In fact, this reminds me of DBD::AnyData which has some proxy-like support and might also support a crypto wrapper.

It strikes me as a really bad idea to distribute social security numbers, encrypted or not. I assume you'll include the decryption key with the program, perhaps inside of it? This means your high value data is effectively not encrypted at all. This is a perilous thing you've asked about. Be good.