Lab Requirements:

Setup

$$ Download and install $$Linux Ubuntu $18\mathrm{.}04\mathrm{.}2$ LTS version or any later version$$ Virtual

Machine at your VMware Workstation or VirtualBox.

Objectives:

After completing this lab, you will be able to:

$$ Encrypting files or data by using different types of symmetric cipher techniques.

$$ Decrypting encrypted files.

Task#$1$: Encrypting and decrypting files by using AES$256.$

Step# $1$: Encrypting file by using AES$256$

$1-$ Log in to your Linux Ubuntu VM

$2-$ List below the cipher with PGP after running this command

gpg $$version

Note: When you use a symmetric cipher to encrypt $/$ decrypt data or files, you will be

asked to enter a passphrase and then confirm it$.$ Your passphrase must be strong and do

not forget what you chose.

$3-$ By using cat command, you can create a file with the name $$ao$123-$ please use your

name convention $$ and then press enter

Write the following line as a text inside this file:

$$This is my file which will be encrypted by AES$256$

Press Ctrl$+$D to exit the editor

$4-$ use the $--$cipher$-$algo AES$256$ option to encrypt a file called ao$123.$txt

gpg $--$symmetric $--$cipher$-$algo AES$256$ ao$123.$txt

Enter your own Passphrase and confirm it again.

$5-$ Check files in Linux as shown below, you will find there is a new file with the name

ao$123.$txt$.$gpg is generated.

Open the content of this file by using cat command as shown below.

Here your file is encrypted by using AES$256$ cipher.

Step# $2$: Decrypting the encrypted file.

$1-$ To decrypt your file $$ use your file name $,$ you need to run:

gpg $-$o original$\_$file.txt $-$d ao$123.$txt$.$gpg

$2-$ Check files in Linux again, will find there is a new file with the name original$\_$file.txt is

generated.

$3-$ Double click on the original$\_$file.txt file, you will get decrypted file as below.

Task#$2$ : What to do:

By repeating step$1$ and step $2$ of Task #$1,$ answer the following questions by providing the required

screenshots:

a$.$ What is Pretty Good Privacy $($GPG$)?[0\mathrm{.}5$ Mark $]$

b$.$ Create a new text file $($ao$123\_$new$).$check note $2$ for the file name$[0\mathrm{.}5$ Mark $]$

c$.$ Run Twofish to encrypt the new file and generate the cipher file. $[2$ Mark $]$

d$.$ Run Twofish to decryption on the cipher file. $[2$ Mark $]$

e$.$ Run $3$DES to encrypt the new file and generate the cipher file. $[2$ Mark $]$

f$.$ Run $3$DES to decrypt on the cipher file. $[2$ Mark $]$

g$.$ Conclusion: write what you learned from implementing assignment #$1.[1$ Mark $]$