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[SOUND] We've developed
a basic visual model for

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Internet traffic to help
us make informed decisions.

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We've also toured some of the more
common threats and effective defenses.

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Now it's time to level up our own online
behaviors to stay safe and secure.

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One of the more important tools that
we have available to us cryptography.

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The movies can make it seem like
cryptography is only used for

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international espionage.

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But the reality is that most
of us use it nearly every day.

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Without going into the details,
this video will introduce encryption and

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related tools that help make using it
as easy as sending a text or an email.

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Cryptography is a great tool because
it offers a form of defense for

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many of the attacks or
threats we've already discussed.

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And best of all,
you're likely already using it.

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In our last video, we talked about HTTPS.

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This secure version of HTTP,
the main communication of the Internet,

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offers protections from eavesdropping and
from man-in-the-middle attacks.

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Cryptography, at least for

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our purposes, is the use of advanced
mathematics to serve this double purpose.

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First, it provides guarantees
of authenticity by

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ensuring the participating parties
are who they say they are.

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This could be you and
another person, or your computer and

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a website hosted in
another part of the world.

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And second, it protects privacy by
encrypting the contents of a message

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in such a way that only the proven
participants can decrypt and read it.

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Often, this happens seamlessly,
such as in the browser for HTTPS traffic.

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Another seamless integration
is Apple's iMessage,

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the built-in text messaging
between iOS devices.

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These messages are also protected
with strong cryptography without

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complicated setup required from users.

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Let's explore other ways to use
cryptography to get these benefits for

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the rest of our digital information.

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We can categorize the digital information
in our lives into data in transit and

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data at rest.

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This can help us tools the right tools for
the job.

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Data in transit relates to the active,
communicating messages.

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This could be sending an email or
a text message, but

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this could also include
browsing a webpage.

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The implied risk here is that
the active transmission in vulnerable.

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So what are our options?

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Fortunately, quite a few.

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Data in transit.

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Web Traffic- https.

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Look for it in the address bar, and
that it shows the right domain.

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Additional tools like HTTPS Everywhere

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can help use only secure
sites wherever possible.

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Email, several options exist and
more are in development.

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Third party services provide encrypted
emails such as ProtonMail or RiseUp.

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Other solutions like Enigmal allow you to
keep your existing e-mail address, and

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can encrypt the content of your messages.

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Text messages.

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Two big players in the field at
the moment, Signal and WhatsApp.

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They're based on similar technologies so

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their discerning features are more about
design choices and supporting companies.

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VPNs.

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We spoke briefly about virtual
private networks already

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as a way to protect your internet traffic.

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But it's worth repeating here.

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Countless VPN services are available, so

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it will take some research to
find the best fit for you.

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Data at rest relates to the act
of storing information.

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This could be everything on your
hard drive, or an external drive, or

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even how your email and
text messages get saved on devices.

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The risk here is a bit more obvious.

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If someone gained access to these devices,
what information could they capture?

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There is no shortage of solutions for this
category either, so let's jump right in.

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Data at rest, system encryption.

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Often, there's a simple setting to
be switched on for a given device or

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operating system, and

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it's usually accompanied by
providing a strong passphrase.

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For example, on Window's
machines it's called BitLocker.

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And on Mac OS, it's FileVault.

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It is highly recommended to enable this
when possible on all your devices,

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whether a desktop, laptop,
cellphone or tablet.

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Drive encryption, some built-in
tools allow individual files and

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folders to be protected
with basic encryption.

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Other third party tools
have seen greater adoption.

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Windows, Encrypted File Service.

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macOS, Disk Utility.

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VeraCrypt is a free, open source utility
that improves upon another well-known,

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but now abandoned, tool, TrueCrypt.

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Third party tools.

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Other tools offer different levels of
protection with varying degrees of

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usability and cost.

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GPG is a tried-and-true command-line
multi-tool that can cover just about any

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need, if you can figure out how do
you construct the correct command.

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Keybase is an interesting service
that offers various cryptographic

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functionality, including encrypted
chat and shared file-system.

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Now we've seen how beneficial
cryptography can be.

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We've also explored ways that it
has already improved our lives.

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And, finally, we've learned about some
additional tools to protect our data,

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both in transit and at rest.

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All this without needing to dig into
the messy details of the mathematics