Bruce Schneier wrote the finest book on the subject of encryption ever written. The book, Applied Cryptography: Protocols, Algorithms, and Source Code in C was published in 1993. What little I know about encryption, I learned from this book. It was well written and covered a difficult subject brilliantly. I will never be able to say enough good things about this book!
Note, Amazon indicates that there is a newer 1996 edition available:
I mention who Bruce Schneier is because he gives a few tips on keeping your information as private as possible in an article in The Guardian:
For those of you just looking for a quick summary of the software links:
GnuPG is a “… complete and free implementation of the OpenPGP … allows to encrypt and sign your data and communcation”
Silent Circle is a $10/month service that secures mobile devices voice, text, video, and file transfers. I don’t know if I would ever use it, but it might be worth looking into.
Tails is a live boot operating system. You use it with either a DVD or a USB stick. You can use the internet a little more anonymously. You can reduce your traces while using the internet. It provides state-of-the-art cryptographic tools to encrypt files, emails and instant messaging. This is well worth a little time.
OTR, Off-the-Record-Messaging. It is a plug-in that works with XMPP protocol chat clients. There is an example in a video file tutorial on the site for using the pidgin.im client with a jaber.org account. If you need secure chat, worth looking into.
BleachBit is an open source program that can shred files securely and automatically clean up those annoying temporary internet files the are created when browsing the net. Well worth looking into.
Password Safe is an open source program for securely storing your passwords. It’s free and secure. Look into it.