It is now trivially easy to encrypt any text such that only I can read it. If you follow the instructions below, you can create a message that nobody but I can decrypt it, not even the sender. The advantages of this should be obvious, and I reccommend that you never send unencrypted email if you know the recipient's key.
Download a copy of PGP International, which is available for nearly all computers, in a variety of versions. You may find version 6.5 useful, as it gives lets you create an encrypted area on your computer also.
Install PGP. You will be prompted to create your own encryption key, which comes in two parts: [1] a public key, which anyone can use to encrypt messages to you, and [2] a private key, with which you can read such messages. Send your public key to everyone you know.
Import my public key. It's listed below, in the purple box. Select it, copy it, and from PGP's padlock-icon menu, select "Add key from clipboard"
Congratulations, you're almost done! Copy the text of your email, and select "encrypt clipboard" from the PGP menu. Double-click on "Oliver White" (that's me) and click OK. Paste the newly-encrypted text back into your email and send it to me.
Of course, you can adapt these instructions for sending encrypted email to anyone, not just me. That's left as an exercise for the reader ;-)
If you're interested to find out more about how cryptography can be used in practice, there's a great book about it, disguised as the PGP manual. It's available on the PGP website, or part of the package when you download PGP.
For people even more interested, try Bruce Schneier's books: Advanced Cryptography is about the technical aspects (how to sign emails, how the various cyphers work and how to code them), while Secrets and Lies is about the human aspects (such as the euphamistally-named 'rubber-hose cryptography', and why the weakest-link is always human)
-----BEGIN PGP PUBLIC KEY BLOCK----- Version: PGPfreeware 6.0.2i mQGiBDr0DVYRBADrbZiHLCtnMiP780Ic+ylyUZlNqNbLfA6oAQ3lPwzuXJpjD4sO /FVCU9RyPfMQUJYbViukKgPBBP9Ggsp7ruiaHGR4sQFIHCg7ikjLl1ZCQZ07zdKP yp7dyb4ZLXj5oMXHJnYmIhEartKCIZNYx8W27vloJyf6t5xKUpUxlnEYJQCg/8wV VLFrYqhuUysqH0sFmkFYEC8D/1+02yeKquaCfdsflbmK5WJv2xCKgTam2HDGDm9p amneiCTf4Qc5Huq90uHQMvmgZY6zZStA234/l4TBdncgJFcX4jO3a9wkXlc/ijkn Lz+DhFXm3nAvkqcMDJv7D2r62lCkH/q0uyPWibwOBN7D5xzs1hSpa/3phXdb7azr qGlsBACv7lzLSb8k6I4HM51hjJh7fzO/JAZqz9tlnE82ojv5Ui7gHiTsRfnV7nqz vUq74rteKBwkgemXDrYNQtsKRDAFR9nx1dVqzZrADU+oW2w5XTwmzUEMMqAsYFHg e4ihk/L01j6fGFl5RT6ApWa9i9pX+Vb/j6ytG8eqlOei2USWBrQwT2xpdmVyIFdo aXRlIDxvbGl2ZXIud2hpdGVAYmxpYmJsZWJsb2JibGUuY28udWs+iQBKBBARAgAL BQI69A1WBAsDAgEACgkQO5ktUuGvN6GPXwCXSj8TjdVaf7HoAfOyUhsoWRB1tACg kfBeNWqBnOIk46F1LW751RYROoG5Ag0EOvQNVhAIAPZCV7cIfwgXcqK61qlC8wXo +VMROU+28W65Szgg2gGnVqMU6Y9AVfPQB8bLQ6mUrfdMZIZJ+AyDvWXpF9Sh01D4 9Vlf3HZSTz09jdvOmeFXklnN/biudE/F/Ha8g8VHMGHOfMlm/xX5u/2RXscBqtNb no2gpXI61Brwv0YAWCvl9Ij9WE5J280gtJ3kkQc2azNsOA1FHQ98iLMcfFstjvbz ySPAQ/ClWxiNjrtVjLhdONM0/XwXV0OjHRhs3jMhLLUq/zzhsSlAGBGNfISnCnLW hsQDGcgHKXrKlQzZlp+r0ApQmwJG0wg9ZqRdQZ+cfL2JSyIZJrqrol7DVekyCzsA AgIIAKH/jCGINCeRys9TK7iqNzGhW4uKcKr4FJzhvBg9dh2k5o0WYHhtPsQu4ZU7 AN8U1fAxVmrbQdIch+W4rJL/JItaRQw+kVF483h/6aG093Nczw0u83gj4fxn4I9l I4OTH4WL/gyXPQxiwcTtuUsIVPTp5kPkNiYll7vJY92dMJRtIHZo4mEj/5LqGpk7 wZgACNPLXBWGTj/ejQMpaGTJpOId/B++mvg1vRiwgJDu40DeAfxkxflNdyvpYCuy oF/tCPQBtBJmPhAijwUTIsUVFLTeb7l9h50RN2a/qWHpmhYvtZvtOIw21WEEfVec IlOXNGOP/huQiDsea/PeFY2/idSJAEYEGBECAAYFAjr0DVYACgkQO5ktUuGvN6Hx CgCgrT+nA3L37tGdt8q6JS50kYvb/88AoIscKlStpzgLN1GK+HTX04BrmQRouQIN BDrzQoAQCAD2Qle3CH8IF3KiutapQvMF6PlTETlPtvFuuUs4INoBp1ajFOmPQFXz 0AfGy0OplK33TGSGSfgMg71l6RfUodNQ+PVZX9x2Uk89PY3bzpnhV5JZzf24rnRP xfx2vIPFRzBhznzJZv8V+bv9kV7HAarTW56NoKVyOtQa8L9GAFgr5fSI/VhOSdvN ILSd5JEHNmszbDgNRR0PfIizHHxbLY7288kjwEPwpVsYjY67VYy4XTjTNP18F1dD ox0YbN4zISy1Kv884bEpQBgRjXyEpwpy1obEAxnIByl6ypUM2Zafq9AKUJsCRtMI PWakXUGfnHy9iUsiGSa6q6Jew1XpMgs7AAICCADLA/EeSA9QB0OTHpMq9KHinlhA 51kFzX4bCvQ85NFUPgeeAeiJR1T+5P6aX4Jt3TSylDsS34Xm645dTxUd4ULgTqbN +GjH4aVuo0XvW3+JXH+llPRjMiSsvfuCfsGcAmOjwHJBlFtqLtcZzGEddJ9epObR +TrGRwFU62YMjIOOLSowwkdZ5m08o7PWIE7vkhq+xzxPfu92znqx/yjRpblciybU ZloxVg3s+uNA1CvBN5CGP/wSMTNiFvJsqqA7SkM+yWcDy0b39NzsQ5rkPluPUtUd Auv1/1Z1bMf1bdUT8le2PEAEy7WUVn/gIrxJK3YQS1xRJpP7Q9lI47g9mq4eiQBM BBgRAgAMBQI69BaIBQkBPGgAAAoJEDuZLVLhrzehB8YAoIsL48BElqKxEmtZFvdP /WljFPKGAJsFF+iAXhAAFFmiKNn266zhYEaZ0w== =FQxd -----END PGP PUBLIC KEY BLOCK-----
Although you should make every effort to share your public key, attach it to emails and display it on your website, you may occasionally need to find a stranger's key.
You can sometimes use the public keyservers here, but beware that you have no idea whether the key is owned by the person it claims to be.
The best way is to email someone and ask for their key before sending any real information by email. This reduces the risk of getting the wrong key, although you should phone them to check the fingerprint of their key matches the copy you hold.
Note: if you do a search for me on the keyserver, you'll find two keys. One of those has been revoked
