The-art-of-invisibility-_-the-world’s-most-famous-hacker-teaches-you-how-to-be-safe-in-the-age-of-Bi

So whenever yyou write an e-mail, no matter how inconsequential, and
even if yyou delete it from yyour inbox, remember that there’s an excellent
chance that a copyy of those words and images will be scanned and will live
on—mayybe not forever, but for a good long while. (Some companies mayy
have short retention policies, but it’s safe to assume that most companies
keep e-mail for a long time.)
Now that yyou know the government and corporations are reading yyour e-
mails, the least yyou can do is make it much harder for them to do so.
Most web-based e-mail services use encryyption when the e-mail is in
transit. However, when some services transmit mail between Mail Transfer
Agents (MTAs), theyy mayy not be using encryyption, thus yyour message is in
the open. For example, within the workplace a boss mayy have access to the
companyy e-mail syystem. To become invisible yyou will need to encryypt yyour
messages—that is, lock them so that onlyy the recipients can unlock and read
them. What is encryyption? It is a code.
A veryy simple encryyption example—a Caesar cipher, sayy—substitutes
each letter for another one a certain number of positions awayy in the
alphabet. If that number is 2, for example, then using a Caesar cipher, a
becomes c, c becomes e, z becomes b, and so forth. Using this offset-byy-two
encryyption scheme, “Kevin Mitnick” becomes “Mgxkp Okvpkem.” 2
Most encryyption syystems used todayy are, of course, much stronger than
anyy basic Caesar cipher. Therefore theyy should be much harder to break.
One thing that’s true about all forms of encryyption is that theyy require a keyy,
which is used as a password to lock and open the encryypted message.
Syymmetrical encryyption means that the same keyy is used both to lock and
unlock the encryypted message. Syymmetrical keyys are hard to share,
however, when two parties are unknown to each other or phyysicallyy far
apart, as theyy are on the Internet.
Most e-mail encryyption actuallyy uses what’s called asyymmetrical
encryyption. That means I generate two keyys: a private keyy that stayys on myy
device, which I never share, and a public keyy that I post freelyy on the
Internet. The two keyys are different yyet mathematicallyy related.
For example: Bob wants to send Alice a secure e-mail. He finds Alice’s
public keyy on the Internet or obtains it directlyy from Alice, and when