< All CompTIA Security+ Notes

# tsirhCdneM | CompTIA Security+ | Module 6

By: Raul Pop | Related Course: CompTIA Security+ | Published: June 3, 2017 | Modified: June 3, 2017
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## Block/Stream Cyphers

Block cyphers

A block Cypher will take information to be processed and process it in block sizes, specific block sizes. You would be told that the block Cypher in either 56 bit blocks or 128 bit blocks.

Stream Cyphers

Stream cyphers on the other hand will take information to be encrypted individually or in bits. So a stream cypher will work in this fashion. Take that, encrypt it one at a time, individually or in bits we say. So stream cyphers work this way, encrypting one character at a time until the entire message is encrypted. For this syllabus, the only stream cypher we have to discuss is RC4.

## Cryptography Concepts

Symmetric key Encryption-only 1 key is used

Asymmetric key -public key

– private key

Dan needs to send adam a message to ensure confidentiality how should dan encrypt the message

A) Use Dan’s Public key => not a solution

B)Use Adam’s Private Key => not a solution

C) Use Dan’s Private key => authenticity not confidentiality

D) Use Adam’s Public Key => this is the solution

## DES/HMAC/CHAP

Data Encryption Standard(DES)

3DES

Hash base Message Authentication Code(HMAC)

RSA

RC4

Challenge Handshake Authentication Protocol(CHAP)

Comparative Strength of algorithms

Key Stretching

## Hashing/Steganography

Example

The ball is moving well=N56BACTUSAQA(Hash value) you can check for integrity and see changes

The ball is moving great=>different value so is  not collision resistance if the ”text/file” is modified.Can be collision resistance if the message is not compromised

Hashtag

Capture evidence

-Hash the original

-Capture image of original

-Hash of the image

Steganography

Hide information in another information.(Text in an image)

-Carrier File=>Carried Files

## MD5,SHA,AES

Message digest algorithm(MD5)

Secure Hashing Algorithm(SHA)

## Public Key Infrastructure

Core of Public key Infrastructure(PKI)

PKI

Symmetric Key

-Public Key

-Private Key

Registration Authority

key Escrow

Recovery Agent

CA-Certificate Authority

CRL-Certificate Revocation list

## Transport Encryption

Internal network=>VPN Connectors=> VPN Internet=> Remote Users

VPN=Virtual Private Network

Creates a tunnel/virtual network

## WEP/WPA/WPA2

Secure wireless traffic

1)WEP-RC4

-initialization vector attack victim

-weakness

2)WPA-TKIP=Temporal Key Integrity Protocol

3)WPA2-CCMP/PSK

< All CompTIA Security+ Notes
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