# Crypto Algorithms pt1

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00:01

Welcome to Cyber Aires. Video Siris on the comedy A Security Plus 5 +01 Certification and Exam.

00:07

I'm Your Instructor, Round Werner

00:11

in the first section for Domain six on Cryptography and P. K I. We just scratched the surface talking about the basic terms and concepts

00:19

in this section, we dive deeper into cryptographic algorithms and their basic characteristics.

00:26

Cryptographic algorithms could be divided into three following groups. Symmetric,

00:33

asymmetric and hash functions.

00:36

Crypto systems are made up of a combination of these algorithms, providing capabilities to ensure the confidentiality and integrity of data and files and network streams.

00:47

Be sure that you understand the differences in the various algorithms and their operations that you can select strong and appropriate crypto systems.

00:55

Given the number of topics, this section will be divided into two videos.

01:00

The first video for section six dot to I'll cover obfuscation, symmetric algorithms and cipher modes.

01:07

And the second part I'll cover asymmetric algorithms hashing and key stretching

01:15

before diving into the details of cryptographic algorithms. It's worth exploring the means of obfuscation.

01:22

Recall fromthe last video. That reputation by itself usually doesn't provide strong security.

01:29

However, obfuscation techniques play a role in many of the crypto algorithms used.

01:34

A common obfuscation technique is a substitution cipher. For example, R. O. T. 13 rotate 13 rotates 13 places in the alphabet. You see the example on your screen.

01:49

There are many other types of substitution sze ciphers that provides that level of confusion. Obvious cation.

01:59

The exclusive or or X or function is often used in cryptography with other streaming operations.

02:07

The X or operation usually comes before or follows another encryption operation

02:13

because X or works bit by bit in a stream. It lends itself well to working with different, different cryptographic modes of operations to turn block ciphers into stream ciphers.

02:24

I'll explain how it works.

02:28

The true value number one

02:30

is derived on, Lee won. The two comparisons are mutually exclusive or different.

02:37

They are exclusive or they're not, in which case the output is false. The number zero

02:44

see some examples on your screen, so if we have zero and zero, so two of the same should be false. Same thing with two of the same one. But if it's a 011 or zero, each of those produces the output of true or one

03:00

the way this works with encryption, you see, is a secret key, and that secret key could be some type of a pseudo random bit value. Using Byner,

03:10

where it's X ord.

03:13

To create the safer text,

03:16

you can use the same key, same binary key

03:22

going backwards to get the initial value.

03:25

Be familiar with X, or there's about its heavy of math, as you may see with the security. Plus,

03:31

we use this a lot, not only within cryptography

03:36

but also within networking.

03:39

The first set of videos in this domain introduced you to the concept of symmetric encryption,

03:45

in which the sender and receiver used the same shared key or an identical key. Symmetric

03:53

Smith Trick algorithms could be classified as either block ciphers or stream ciphers. As the name implies, Stream cipher encrypts the message bit by bit, one at a time,

04:02

while the block cipher encrypted messages in chunks. Known sets

04:08

go back to that previous video

04:10

to review the idea of stream cipher versus block cipher.

04:15

Several symmetric key algorithms are in use today.

04:17

More commonly used algorithms include Triple Dez and A S. I'll talk about D s, the data encryption standard,

04:26

and then tripled as on this slide and eight yes, on the next light

04:31

does is the first symmetric algorithm I'll discuss.

04:35

It was first adopted by the U. S National Institute of Standards and Technology, or Nest in 1977. It's a block cipher using 64 bit blocks,

04:46

a 56 bit key with eight bits of parody.

04:51

Be familiar with those numbers. I've often seen test questions that refer to them.

04:57

So Dez 64 bit blocks 56 bit key

05:01

has a short key length, which is subject to brute force attacks.

05:08

Therefore, n'est had to come up with a different algorithm, but it's based on death. It's called Triple Dez.

05:15

It's the Dez algorithm, computed three times. You see an example on your screen.

05:23

It uses a key bundle that comprises three different days keys each 56 bits with a total *** strength of 100 and 68 bits

05:35

known as three t D E. A.

05:40

There are options to reuse the keys, but that reduces the key Strength.

05:46

Triple does is still in use. Today,

05:50

A yes or the advanced encryption standard has replaced. As as the current standard, it uses the right stall algorithm based on the names of the people who developed it.

06:01

A s is the product used by U. S government. Endorsed by the National Institute of Standards and Technology.

06:09

It supports key size of 128 192 and 256 bits.

06:15

It's free

06:16

for any use, public or private, commercial or non commercial.

06:20

Your call from an earlier video

06:24

knowing the algorithm is perfectly acceptable. It's keys that need to be kept secret.

06:30

It uses multiple encryption rounds,

06:32

10 rounds for 128 bit keys, 12 rounds for 100 and 92 big keys

06:39

and 14 rounds for 256 bit keys.

06:43

It's a block cipher using 128 bit block sizes

06:48

rather than me explaining all of the intricate details associated with A S. I recommend you go to the website shown on the screen.

06:58

The creators not only do a good job of educating on a yes, it's also rather entertaining how they use stick figures and humor to explain very deep concepts. With the advanced encryption standard,

07:12

I recommend you check it out.

07:15

There are other symmetric algorithms that you need to be familiar with

07:19

first being R C four, named after Ron Riv EST Ron Cipher or Rive est ciphers. It's the fourth iteration.

07:29

It was popular with Webb and W. P. A encryption used in wireless.

07:34

RC four is a streaming cipher that worked with key sizes between 40 and 2048 bits,

07:43

and he used with S S, L and T L s with network level encryption

07:49

Blowfish. It is an encryption system invented by team, led by Bruce Schneier, that performs a 64 bit block cipher at very fast speeds.

08:01

It is a symmetric block cipher that uses a variable length key from 32 bits to 4 48 bits

08:09

to fish is quite similar and works on 128 bits blocks

08:16

three other symmetric algorithms you should be familiar with. First being idea. The international data encryption algorithm

08:24

this is used over in Europe has 128 bit key,

08:31

and it's similar to Dez. But it's more secure because it has a longer key

08:37

used within the application. Pretty good privacy, which we'll talk about in the future. Video.

08:43

A one time pad is the most secure cryptographic implementation it uses a key that as long as the plain text message. So let's say you're plain text. Message is one page in length.

08:56

The key would be one page and length.

09:00

It's a very strong,

09:01

not very efficient, too, though

09:03

one time pad is used once and then it's destroyed.

09:09

The third algorithm is Skipjack. It was developed by the N S A. It's a block cipher that was used in the Clipper chip but mostly historical reference.

09:20

It uses an 80 bit key to encrypt 64 bit blocks of data.

09:26

Be familiar with each of the symmetric algorithms. You'll see them out in the world and potentially on the security plus exam.

09:35

We'll now talk about cipher modes. Recall from earlier stream versus block. Ciphers will block ciphers, have many different modes of operation.

09:46

The following gives some of the more common mode, especially the ones you should be familiar with.

09:52

First, being CTR Counter Mode turns a block cipher into a stream cipher.

09:58

It's used to generate a key stream.

10:01

Aqui Stream is a stream of random or pseudo random characters that are combined with a plain text message to produce an encrypted message or the cipher text

10:11

the characters in the key stream can be bids by its numbers or actual characters like a through Z, depending on the use case.

10:20

Each block combined a nonce or initialization vector with a sequentially assigned a number to produce a unique counter block

10:28

that is then encrypted

10:31

cipher block Chaining uses that initialization vector ivy with the first block

10:37

they're after. Each block of plain text is obvious. Skated with the cipher text from the previous block before it is encrypted, so it's using blocks and taking from the first to go to the next.

10:50

It introduces Maur diffusion

10:52

and reduces effects of blame of plain text attacks.

10:58

GCM Gail Oi counter mode provides both integrity and confidentiality. It's a cipher boat

11:05

they uses CTR, but with 128 bit blocks. Each block is then given an encrypted number. That result is obfuscated with the plain text producing the cipher text

11:18

G Mac or Careless Message. Authentication code is an authentication on Lee Variant of GCM, which is which can be used with an incremental message authentication mode,

11:33

E. C B or Elektronik who'd book divides the message into blocks

11:37

and then encrypt each block.

11:41

It's no longer recommended because the same plain text block is encrypted in the same safer text block each time, so it's easily compromised.

11:50

Review these different types of cipher modes to prepare yourself for the security plus exam.

11:58

We've talked about just a few of the symmetric algorithms, cipher modes and talked about a few station.

12:03

Let's practice on a few quiz questions.

12:07

This block Cypher uses a key bundle that comprises three different days. Keys

12:13

each 56 bits.

12:16

The answer is

12:18

D triple Daz

12:22

question, too.

12:22

This cryptographic algorithm works by generating a key stream block by encrypting sequential values of some counter and is used to convert a block cipher into a stream cipher.

12:35

You call. We just talked about seif remote, so the answer is B C T R.

12:43

This is the end of part one, where we're explaining cryptography algorithms and their basic characteristics.

12:50

Part two will continue this discussion on section six dot too

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