How to download website | best program

Sometime we need browse site offline as online , by download it in your computer . There are some tools use to download whole site , some are good and other bad , here we discussing best tools or program use to download entire website .

HTTrack Website Copier is program use to downloading website , it's free and easy to use . HTTrack download Html ,image and other file from server to your computer .after downloaded you can open page offline as an online site ,It's arranged and view like online .

How to use HTTrack  ?

First download HTTrack from original site from this link :

Download Httrack Free  

Install it in your computer and open program to make new downloading website : 

This is main window .. click in Next .. 

 Now Enter project name ,add any name . And base path , mean where you want to download website in your computer .. and click Next .. 

Now Add url of any website you want to download it , if you need to download my blog enter my website url : http://computers-easy.blogspot.com/ , after enter Next .. 

Here you have additional option :

Disconnect when finished : When website finishing download will disconnect form internet .

Shutdown PC when finished : After website finishing download will shutdown your computer . 

Save settings only . do not launch download now: If you need to save project name with option you add and downloading another time ,click this radio button .

After that click finish to start downloading and copy website to your computer .

When download finish you can go to file you save website on it and find index.html file ,, it's the main page of website .

Advantage :

• Free .
• Easy to use .
• When browse website in your computer is look like online website .

Disadvantage :

• Take long time to download website . 
• If downloading stop , you can't make resume download , you need to start new download .

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What is Symmetric Key Encryption

Symmetric Key Encryption is one of Cryptographic Tools use for secret communication , some times called conventional encryption or single-key encryption .

This diagram explain algorithm :

We have in diagram 5 things , plaintext , encryption algorithm , secret key , decryption algorithm , and ciphertext .

How algorithm run ?

Plaintext : Our message we need to transfer to another side , it's our in put that fed into encryption algorithm .

Encryption Algorithm :It's do some substitutions and transformations on the plaintext , to encrypting plaintext by using secret key information .

Secret key :It's have information that need to encryption and decryption .

Decryption Algorithm : We can say reverse of encryption , take ciphertext and by using secret key to decryption message to original plaintext .

Ciphertext : scrambled message encrypted by encryption algorithm using secret key information and transfer to other side , it will be input to decryption algorithm , and by using secret key will be original plaintext .

To make this symmetric strong we need tow things :
first : strong algorithm , to encrypting message .
second : secret key must keep secure .

Tow way to Attacking Symmetric Encryption :
1- cryptanalysis , to use it we need some knowledge of the general characteristics of the plaintext .
2- brute-force attack , we try all possible keys until plaintext is obtained .

Sources: Computer Security: Principles and Practice by William Stallings and Lawrie Brown .

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