- Hackers can break a code.
But can they break the laws of physics?
(upbeat techno music)
Secrets are an amazing adaptation.
I mean, think about it.
Trees don't have secrets.
Bacteria don't have secrets.
It's only creatures that have a complex brain
that can realize that withholding privileged information
can give you an advantage over others.
And if you look at the history of technology,
you see lots of examples,
from combination safes to the enigma machine,
of people trying to keep secrets safe.
Meanwhile, other people are trying desperately
to uncover those secrets.
Now, if you use the internet a lot,
you've probably transmitted some pretty private information,
like your credit card or bank statements,
or maybe even just a photograph you hope never sees
the light of day.
To do that secretly so people can't look in
on what you're sending,
you have to mix that message up using an encryption key.
A very common one is public key encryption
using prime factorization of a really big number.
Basically that means you're making a really
difficult problem to solve mathematically,
even for a computer.
The way it works is that I would have both a private key
and a public key.
I could share my public key with whoever I like,
like you.
I like you,
and you wanna send me a message.
You use the public key that encodes the message.
The private key decodes the message.
The only other way to decode that message would be
to do that enormous computer problem
that would take the average computer hundreds of years
to solve.
That's why you don't necessarily worry about an eavesdropper
looking in.
But, what if the eavesdropper has a quantum computer?
Quantum computers aren't just hypothetical.
Leaked documents from the NSA show that that agency
is extremely interested in pursuing that particular
technology.
So, does this mean that digital privacy is at an end?
Well not necessarily.
Maybe we can look in to quantum cryptography.
This is a different approach.
Instead of having a private key and a public key,
I just have two private keys.
So whenever I want to communicate with you,
I send you my private key and the two of us
can communicate together.
Now this key is not made up of ones and zeroes,
instead it's made up of photons,
particles of light that have a certain spin,
like vertical, or diagonal, or so on.
So based upon the quantum state of the particle,
I can encode the message and it's sent to you,
and it's perfectly safe.
But, I know what you're saying.
What if the eavesdropper is listening when I send you
that private key?
Aha!
Well, I'll try and boil this down to be as simple
as possible,
but based upon the laws of quantum mechanics,
it don't work that way.
Cause just by looking at the private key,
it alters the key.
So if I send you a private key,
and it's not the right formation,
we know someone was eavesdropping,
and the solution is just to send another private key.
If that one's altered, send another one.
Just keep doing it until the snoop is tired,
and then we can communicate in secret.
So does this mean that quantum cryptography
has made digital privacy safe forever?
Probably not.
Now, it's true that in this quantum state,
we're pretty safe.
I don't really see a way that a hacker could get at
that information,
but that assumes a perfect implementation,
And we humans aren't so great on perfect.
For example, you might've heard of the heartbleed bug
that plagued us back in April 2014.
That wasn't some sort of inherent flaw
in public key encryption.
That was actually a problem with the open SSL library,
something that we humans are in charge of.
So even with a perfect system,
just keep in mind that you, the user, are a weak link.
It doesn't matter how great the lock is
if you're just handing the key out to everybody.
So it's important not just to design the best system,
but to train ourselves in the best ways to keep ourselves
secret, safe, and private.
Now that leads me to a question for all of you this week.
Do you think digital privacy is in our future?
Or will all of our secrets be laid out bare to everyone?
Let me know in the comments below what your thoughts are.
And if you enjoyed this video,
make sure you hit like and subscribe to the channel,
don't keep it a secret, share it with your friends,
and check out these videos over here.
(techno music)