The best way to ensure that private information stays private is to keep it all in your head and never divulge it unless tortured! That ain't going to cut it in this day and age when we have more than a few things to remember. The most common way is to use some kind of data safe where information can be stored with some level of privacy.

Now, a disclaimer about this post and use of technology in securing your secrets. There are many ways in which your private data could be compromised. While the underlying math of cryptography seems foolproof with technology we have now, a radically new approach, however unlikely but not impossible, could render it vulnerable. But the good news is that, we can trust the math. And the bad news? We can never trust the implementations. Cryptography implementations are plagued with bugs which can go undetected for years. Many algorithms once considered secure are now considered unfit. Your computer can be bugged at the hardware level. There is a possibility that even a computer not connected to the internet is vulnerable to eavesdropping.

With that said, let's now dive into some practical techniques to protect our documents. The tool we will use is GnuPG which is an implementation of OpenPGP and RFC 4080 . This is a good choice as it is completely open source. In the world of security, an implementation that is reviewed by people all over the world is more trustworthy than a closed implementation where you would have to trust a corporation.