Proj X11: Using RSA with OpenSSL (20 pts)

What You Need for This Project

A Kali machine, real or virtual. Other Linux systems should work too.

Purpose

To practice using RSA to encrypt and decrypt data. This is an important skill for security professionals.

Edward Snowden, the NSA whistleblower, wanted to use RSA encryption to send confidential data to Glen Greenwald, but Greenwald couldn't set it up.

1. Generate a Key Pair

On Kali, in a Terminal, execute these commands:

openssl genrsa -out private_key.pem 2048 openssl rsa -in private_key.pem -out public_key.pem -outform PEM -pubout ls -l

You see two PEM files, one containing a public key, and one containing a private key, as shown below.

Both of those files are plaintext. To see that, execute these commands:

cat private_key.pem cat public_key.pem

Encrypting a Message

Execute these commands to create a file containing your name and encrypt it:

echo "Message from YORNAME" > encrypt.txt cat encrypt.txt openssl rsautl -encrypt -inkey public_key.pem -pubin -in encrypt.txt -out encrypt.dat ls -l file encrypt.dat

An "encrypt.dat" file is created. It's much longer than the plaintext message, and it's a binary file, as shown below.

Decrypting a Message

Execute these commands to decrypt the message and print it out:

openssl rsautl -decrypt -inkey private_key.pem -in encrypt.dat -out new_encrypt.txt cat new_encrypt.txt

The message appears, containing your name, as shown below.

Saving a Screen Image

Make sure you can see your name in the decrypted message, as shown above.

Save a full-desktop image. On a Mac, press Shift+Commmand+3. On a PC, press Shift+PrntScrn and paste into Paint.

YOU MUST SUBMIT A FULL-SCREEN IMAGE FOR FULL CREDIT!

Save the image with the filename "YOUR NAME Proj 11x", replacing "YOUR NAME" with your real name.

Turning in your Project

Email the image to to cnit.141@gmail.com with the subject line: Proj 11x from YOUR NAME

X11.2: Challenge: Decrypt This Message (10 pts.)

Here's my private key:

Download this file and decrypt it.

Enter the plaintext into the form below to record your score in Canvas.

Name or Email:

Plaintext:

Sources

Using OpenSSL to encrypt messages and files on Linux
Thanks to @oADAMo for motivating me to write this project.

Posted 1-24-19 by Sam Bowne