Cybersecurity Fundamentals: Crypto Shields: How Your Data Stays Secret Chapter 3 Part 1

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Have you ever wondered what invisible force protects your private messages, banking details, and personal information as they travel across the internet? The answer lies in cryptology—the fascinating science of securing information through mathematical techniques.

Cryptology forms the backbone of modern cybersecurity, addressing the critical needs for confidentiality and integrity in our digital communications. Throughout this episode, Professor J-Rod breaks down complex cryptographic concepts into digestible, practical explanations that reveal how our online world maintains security.

We journey through the three fundamental pillars of cryptographic security. First, symmetric encryption—the fastest method using a single shared key—powers everything from full disk encryption on your laptop to secure messaging. Next, we explore asymmetric encryption (public-key cryptography), which brilliantly solves the key distribution problem through mathematically-linked key pairs. Finally, we demystify hashing—the one-way process that creates digital fingerprints to verify data integrity without revealing the original content.

Each concept comes alive through real-world examples: how your laptop protects files even if stolen, how websites establish secure connections with your browser, and why changing just one letter in a document completely transforms its hash value. The episode offers both theoretical understanding and practical knowledge about the technologies we unconsciously trust every day.

Whether you're a cybersecurity novice or simply curious about how digital security works, this episode provides valuable insights into the cryptographic foundations that keep our digital lives private and secure. Subscribe to Technology Tap for part two of our Cryptology Deep Dive, where we'll explore digital signatures, PKI, certificate authorities, and applications like VPNs, TLS, and blockchain. Your digital security knowledge journey is just beginning!

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Episode Transcript

Speaker 1 (00:28):
And welcome back to Technology Tap, where we break
down the tech that powers ourworld.
I'm Professor J-Rod and todaywe're diving into one of the
most fascinating and invisibleparts of cybersecurity
cryptology.
Think about it, cryptology.
Think about it Every time yousend a text, buy something
online or stream your favoriteshow.
Cryptology is silentlyprotecting your information from

(00:50):
prying eyes.
But exactly what is it?
How does it work and why do wetrust it with our most private
data?
We'll explore the buildingblocks of cryptology, from
symmetric and asymmetricencryption to hashing and
digital signatures, so you canjust understand how they work,
but why they matter.
Let's get started At its core.

(01:16):
Cryptology is about protectinginformation, making sure the
right people can read it and thewrong people can't.
In cybersecurity, we talk aboutthe CIA triad confidentiality,
integrity and availability.
Cryptology is the key to thefirst two.
Confidentiality encryptionmakes sure that if something
intercepts your message, it'sjust gibberish to them.

(01:39):
Integrity hashing and digitalsignatures ensure that no one
tampered with your data on itsway to you.
Authentication andnon-repudiation digital
signatures let you prove whosent a message and prevent them
from denying it later If youever use HTTPS on a website,
logged into your bank app orupdated your laptop's operating

(02:02):
system, cryptology was workingbehind the scenes.
Without it, the internet willbasically be the wild wild west,
open to anyone who wanted tospy, steal and tamper with data.
All right, symmetric encryptionlet's start with the simplest
and fastest type of encryptionsymmetric encryption.

(02:22):
In symmetric encryption, we usethe same key to encrypt and
decrypt the data.
Think about it like a sharedsecret.
If I lock a box with a key, youneed the same key to open it.
Here is how it works the sendertakes the original message,
called plain text, and encryptsit with a secret key.

(02:43):
The ciphertext scrambles data,it's sent to the recipient and
the recipient uses the same keyto decrypt it back to plain text
.
Because we only use one key,symmetric encryption is very
fast and efficient.
That's why it's used for bulkencryption things like
full-distance encryption on yourlaptop, vpn tunnels, database

(03:06):
encryption and even messagingapps.
But here's the catch Keydistribution.
Both parties need the same keyand getting the key to someone
securely can be tricky.
If an attacker intercepts a keyduring the exchange, they can
read everything right.
So, basically, how are yougoing to give the other person
the key?

(03:27):
Let's talk about some of themost common symmetric algorithms
AES, advanced EncryptionStandard.
The gold standard today isAES-128, aes-129, aes-256.
The number is the key length.
Aes-256 is practicallyunbreakable with current
computing power.

(03:48):
That's today right.
3des or triple DES, an olderstandard that's more secure than
DES, but slower.
Blowfish and 2FISH first, flat,fast and flexible algorithms
popular in embedded devices.
And RC4, once widely used inSSL, now considered insecure.

(04:09):
Imagine your company's laptop.
Or have bit lockers enabledwith AES-256.
Even if a laptop gets stolen,the thief cannot read any files
without the keys.
The lesson here is symmetricencryption is powerful, but you
must protect the key at allcosts.
This is why we often combinesymmetric encryption with

(04:29):
asymmetric encryption, whichsolves the key distribution
problem, and that's what we'llcover next.
Enter asymmetric encryption,also called public key
cryptology.
This is where things get reallyinteresting.
Instead of one key, we use twokeys a public key that you can
share with the world and aprivate key that you keep secret
.
Data encrypted with one key canonly be decrypted with the

(04:52):
other.
Here's a practical example.
I want to send you a secretmessage.
I encrypt it with your publickey.
Only you can decrypt it becauseonly you have the matching
private key.
This completely solves the keydistribution problem.
I don't need to send you asecret key in advance.
Common algorithms here includeRSA, the workhorse of public key

(05:13):
cryptology.
Ecc elliptic curve cryptologyprovides the same security as
RSA, but with much shorter keys,making it faster and more
efficient.
Delphi-hellman, a method ofsecurely exchanging keys over an
insecure channel, often used tonegotiate symmetric session
keys.
So every time you visit anHTTPS website, your browser and

(05:38):
the server use asymmetricencryption.
During the TLS handshake, theserver sends its public key,
your browser encrypts a sessionkey with it and the server
decrypts it with its private key.
From that point on, symmetricencryption like AES takes over
performance.
The downside asymmetricencryption is slower and more

(05:59):
computationally expensive.
That's why it's usually just touse to exchange keys or create
digital signatures, not encryptentire files.
Our last major building blockfor today is hashing.
Hashing is a one-way function.
It takes input of any lengthand produces a fixed length.

(06:20):
Output called a digest.
Key properties is deterministic.
The same input always producesthe same hash One-way.
You can't reverse the hash toget the original input.
Collision resistance it isextremely hard for two different
inputs to produce the same hash.
Avalanche effect change onecharacter, get a completely

(06:41):
different hash.
Popular hashing algorithmsinclude SHA-256, sha-3, hmac for
authentication MD5 and SHA-1.
Md5 and SHA-1 are no longersecure and should not be used.
So the example that I like togive to my students is if you
create a letter, let's say tograndma, and you write her a

(07:02):
long letter and you save it,then you do a hash, you get a
hash file, a hash number.
If you just change grandma tograndpa, you get a completely
different number, right?
Just changing that one letterfrom grandma to grandpa, the M
to the P, changes the hashcompletely.
And the other thing I like totell my students is hashing is

(07:23):
not encryption.
You're not encrypting anything,you're just verifying integrity
.
It's used to maintain integrityon files.
So let's say you uploadedsomething on the Internet and
you give it a hash file.
You want people, people, whenthey download it, to run the
hash to make sure the number isthe same.
If the number is the same, it'sgood.

(07:43):
If it's different, thensomebody broke into your website
, manipulated the file and youdon't want the person to install
it.
Kali Linux used to do it withthe Kali OS, but they stopped
doing it on the when theychanged websites, when they
updated their website.
All right, here's an examplePassword storage.
When you create an account.

(08:04):
Your password isn't stored inplain text, it's hashed.
When you log in, the systemhashes the password you enter
and compares it to the storedhash.
If they match, you'reauthenticated.
Hashing is also used for fileintegrity checks.
Think of downloading an iOSfile from a Linux website and
verifying that SHA-256 hash tomake sure it wasn't tampered
with.

(08:24):
The key takeaway hashing doesn'thide your data, it just gives
you a fingerprint of it.
So today we covered three corebuilding blocks of cryptology
Symmetric encryption for speedand bulk data, asymmetric
encryption for secure keyexchange and authentication.
And hashing for authenticationand verification.

(08:47):
In our next episode we'll putthese pieces together.
We'll talk about digitalsignatures, pki, certificate
authority and real-worldcryptographic solutions like VPN
, tls, blockchain and keymanagement.

(09:08):
Cryptology isn't just theory.
It keeps the modern worldrunning.
Make sure you subscribe toTechnology Tap so you don't miss
part two of the Cryptology DeepDive and keep tapping into

(09:49):
technology.
This has been a presentation ofLittle Cha-Cha Productions.
Art by Sarah, music by Joe Kim.
If you want to email me, youcan at ProfessorJRod at gmailcom
.
You can also follow me onTikTok at ProfessorJRod you.