All platforms with the Java runtime: Free, open source application Sensitive Number Finder (Senf) scans your hard drive for personally identifying data worth stealing, like Social Security and credit card numbers. The software points out these vulnerable digits so you can remove or encrypt them to keep your personal finances or identity safe. Senf requires no installation, so to try it out just download it and run it. The application scans files within any directory and reports on all files that appear as though they could pose a security threat. You're likely to see some false positives, but weeding through them is easy enough, and the peace of mind may be worth it. Senf is free, works on all platforms with Java.