Kind: captions
Language: en
[Music]
When was the last time you sent a coded
message? Well, probably within the last
hour if you sent an email or logged onto
a website. We use codes all the time
because we communicate our private
messages in public. Without codes,
sending information online over
unsecured networks or networks with
security holes would be like standing in
Time Square and shouting your innermost
secrets at the top of your lungs in a
crowd of millions of people doing the
exact same thing. So to protect your
privacy, you have to send your messages
as codes that can be read by your
friends, but not by your
enemies. Codes have played a critical
role in just about every major war in
recorded history. In ancient Rome,
Caesar used a simple code to send
messages to his generals. 2,000 years
later, Allied codereers saved millions
of lives and shortened World War II by
cracking the German Enigma code. But
codes aren't just for emperors and
soldiers. Today, we use them to shop
online and say hi to our
friends. Let's say you want to share a
secret with a
friend. Here's what happens after you
hit send on an encrypted email.
First, your email services need to agree
on a secret key, a very large number
that will be used to lock and then
unlock your message. But they can't just
send that number over the internet
because an eavesdropper could intercept
it. So, they use a brilliant trick
called public key
cryptography. Both sides start with a
publicly available number, but then add
a dash of their own secret numbers and
mix them together using mathematical
operations that are extremely difficult
to reverse. They swap bowls and do it
again. Dash of secret number. Mix it up
and bam, secret key. They used the same
recipe but never shared their individual
secret ingredients. So the key is
safe. Now your email service uses that
secret key to transform and scramble
your message. It transmits the coded
message to your friend's email service,
which uses the secret key to reverse the
scrambles and transformations and reveal
the original
text. Woo! That is a lot of work for one
email, but it happens in the blink of an
eye and without any effort on your
part. The scary thing is not all traffic
is encrypted. Online payments usually
are, but browser history is not, nor are
text messages. Emails are complicated.
They're usually encrypted when they're
sent, but are sometimes decrypted before
they get to their
recipient. Some websites encrypt their
traffic. You can tell by looking for the
lock symbol in a URL. If it's not there,
anything you type into that website can
be intercepted. That's one of the
reasons it's so important to have a
different password for every website you
visit and to avoid unsecure public Wi-Fi
where your messages can be easily
intercepted. The other problem is almost
every code in history has been cracked
in a way that initially seemed
impossible. It could be the case that
there's a in the armor of the
codes we use that no one has discovered
yet. or perhaps someone has and is
keeping that information to
themselves. So, the next time you
metaphorically shout your innermost
secret in public, take a moment to
consider whether you've locked it up
tight enough and what could happen if it
got out.
[Music]