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

Internet traffic to help us make informed decisions.

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

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

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

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

international espionage.

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

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

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

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

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

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

In our last video, we talked about HTTPS.

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

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

Cryptography, at least for

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

First, it provides guarantees of authenticity by

ensuring the participating parties are who they say they are.

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

a website hosted in another part of the world.

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

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

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

Another seamless integration is Apple's iMessage,

the built-in text messaging between iOS devices.

These messages are also protected with strong cryptography without

complicated setup required from users.

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

the rest of our digital information.

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

data at rest.

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

Data in transit relates to the active, communicating messages.

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

this could also include browsing a webpage.

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

So what are our options?

Fortunately, quite a few.

Data in transit.

Web Traffic- https.

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

Additional tools like HTTPS Everywhere

can help use only secure sites wherever possible.

Email, several options exist and more are in development.

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

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

can encrypt the content of your messages.

Text messages.

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

They're based on similar technologies so

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

VPNs.

We spoke briefly about virtual private networks already

as a way to protect your internet traffic.

But it's worth repeating here.

Countless VPN services are available, so

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

Data at rest relates to the act of storing information.

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

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

The risk here is a bit more obvious.

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

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

Data at rest, system encryption.

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

operating system, and

it's usually accompanied by providing a strong passphrase.

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

And on Mac OS, it's FileVault.

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

whether a desktop, laptop, cellphone or tablet.

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

folders to be protected with basic encryption.

Other third party tools have seen greater adoption.

Windows, Encrypted File Service.

macOS, Disk Utility.

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

but now abandoned, tool, TrueCrypt.

Third party tools.

Other tools offer different levels of protection with varying degrees of

usability and cost.

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

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

Keybase is an interesting service that offers various cryptographic

functionality, including encrypted chat and shared file-system.

Now we've seen how beneficial cryptography can be.

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

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

both in transit and at rest.

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