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How do you keep data safe but recoverable?
If you want to, you can go here to learn more about Project Callisto. It's a really interesting project and is open to contributions if you'd like to donate your time and knowledge to it.
If you'd like to know a bit more about asymmetric, or public key encryption, this is an excellent article from Panayotis Vryonis.
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Okay so
you have some data that you need to store.
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You need to be able to get
the data back at a later time.
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Of course while it's stored it should be
unreadable to anyone that doesn't have
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the keys to the data.
0:08
This is where encryption comes into play.
0:09
Encryption is a very broad
area of cryptography.
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But we're going to define it as means of
turning readable data into unreadable data
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and back again.
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Encryption, unlike hashing,
is a two-way street.
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Let me define a couple
of terms real quick.
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First is plaintext, this is the,
well, plain text or
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data that you want to encrypt.
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This is your secret, if you will.
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Second is ciphertext.
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Ciphertext is text or
data that is meaningless by itself.
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Ciphertext is the encrypted
version of your plain text.
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Encryption is the process of
turning plain text into ciphertext.
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Decryption is reversing the process and
turning ciphertext back into plain text.
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Like we talked about before encryption and
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cryptography is a pretty
old area of study.
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People have been writing secret messages
for the vast majority of recorded history.
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For now let's focus on common reasons for
encryption and general methods for
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doing so.
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Like most secret messages like history,
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encryption is most commonly
used in communication.
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When you connect your website, use an SSL
certificate, your communication to that
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website and it's to you about
encrypted and the secret.
1:12
When you send a message to your
friend in an app like WhatsApp or
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Signal that message is also encrypted.
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Communication between two parties is
probably the most common use of encryption
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on today's internet.
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Wait, what's the harm on not
using a secure HTTP connection?
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When you request the URL maybe it
includes some query string parameters or
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has your password in the HTTP
header as form data.
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All of that is visible to anyone that's
tapped in the connection between you and
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the server.
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If you're using HTTPS though,
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that SSL certificate encrypts all of
that data so no one can inspect it.
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We'll cover SSL, in more detail,
in a future course.
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But, for now, check the teacher's notes
for more info if you're interested.
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You might also wanna encrypt data that
you're storing for legal purposes.
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For example, project Callisto is
a college campus focus tool for
1:56
reporting sexual assault.
2:00
Callisto encrypts all reports
before storing them securely so
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that only the reporter can access them.
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You may want to do the same with any
sensitive information provided to you, or
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your users, or internally.
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There're two main styles of encryption
that you'll likely to encounter.
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Symmetric and Asymmetric encryption.
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In symmetric encryption, the plain text is
encoded and decoded using the same key.
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Which means, everyone in
the circles has to have the key.
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If the key is ever compromised, all of
the encrypted data can be unencrypted and
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stolen or abused.
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With asymmetric encryption, everyone has
two keys one private and one public.
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To send me an encrypted message,
you encrypt it using my public key and
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I would decrypt it with my private one.
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Symmetric encryption seems to be
declining in popularity lately.
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But encryption methods such as AES,
blowfish and idea all use it.
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That isn't to say that asymmetric, or
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public key encryption is
impervious to attack of course.
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But attacks on it are often more
difficult than is economically viable.
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Common public key encryption usages
nowadays are things like the off
2:55
the record messaging feature that's
built into mini chat programs.
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Technologies like SSL and SSH are actually
a combination of public and private keys.
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Whatever encryption you decide to use,
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it's often a good idea to keep keys
fresh and stored in a safe place.
3:07
We'll talk more about encryption later but
now is a good time to start thinking about
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place that you might need
to securely encrypt data.
3:14
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