RE: GnuPG...
Hi 2012Tony2012,
The GnuPG package (gpg2, gpg-agent, etc.) is free and runs under Mac OS X, various Linuxes, Windows, and various Unixes. You can encrypt and decrypt on any system that you wish.
You also get to choose the length of your public key/secret keys, so you can make it as secure as you wish. And you can publish your public key on the Internet so anyone can find it. I currently use 2048 bit keys for my own encryptions. I believe the longest PK that has been cracked so far is 64 bits, and that took something like 5 years of effort. They have been working on cracking a 72 bit key for the last 6 or 7 years using the spare cycles on thousands of PCs and are only about 2% done.
Regards,
Switon
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Of course, if Shor's algorithm is implemented on a quantum computer at some time in the future, then these encryption schemes will immediately become vulnerable to attack...
Switon