TryHackMe: Encryption — Crypto 101

An introduction to encryption, as part of a series on crypto

Task 1: What will this room cover?

I’m ready to learn about encryption

No answer needed

Task 2: Key terms

I agree not to complain too much about how theory heavy this room is.

No answer needed

Are SSH keys protected with a passphrase or a password?

passphrase

Task 3: Why is Encryption important?

What does SSH stand for?

Secure Shell

How do webservers prove their identity?

certificates

What is the main set of standards you need to comply with if you store or process payment card details?

PCI-DSS

Task 4: Crucial Crypto Maths

What’s 30 % 5?

0

What’s 25 % 7

4

What’s 118613842 % 9091

Use this python code we can solve this:

print(118613842 % 9091)

3565

Task 5: Types of Encryption

Should you trust DES? Yea/Nay

DES is no longer considered secure for short key lengths (56 bits). AES is now used.

Nay

What was the result of the attempt to make DES more secure so that it could be used for longer?

Triple DES

Is it ok to share your public key? Yea/Nay

Public keys can be shared but private keys cannot be shared.

Yea

Task 6: RSA — Rivest Shamir Adleman

p = 4391, q = 6659. What is n?

n = p * q

29239669

I understand enough about RSA to move on, and I know where to look to learn more if I want to.

No answer needed

Task 7: Establishing Keys Using Asymmetric Cryptography

I understand how keys can be established using Public Key (asymmetric) cryptography.

No answer needed

Task 8: Digital signatures and Certificates

Who is TryHackMe’s HTTPS certificate issued by?

Click on the lock icon to the left of the browser icon. Click on Connection is secure.

Click on Certificate is valid.

Read the certificate.

E1

Task 9: SSH Authentication

I recommend giving this a go yourself. Deploy a VM, like Linux Fundamentals 2 and try to add an SSH key and log in with the private key.

No answer needed

Download the SSH Private Key attached to this room.

No answer needed

What algorithm does the key use?

Open the SSH Private Key attached to this room.

RSA

Crack the password with John The Ripper and rockyou, what’s the passphrase for the key?

We will need to use ssh2john first to convert SSH Private Key to John format.

wget https://raw.githubusercontent.com/magnumripper/JohnTheRipper/bleeding-jumbo/run/ssh2john.py

Now convert the key by using following command:

python ssh2john.py idrsa.id_rsa johnkey

Now crack the password by using following command:

john --wordlist=/usr/share/wordlists/rockyou.txt johnkey

We got the answer.

delicious

Task 10: Explaining Diffie Hellman Key Exchange

I understand how Diffie Hellman Key Exchange works at a basic level

No answer needed

Task 11: PGP, GPG and AES

Time to try some GPG. Download the archive attached and extract it somewhere sensible.

No answer needed

You have the private key, and a file encrypted with the public key. Decrypt the file. What’s the secret word?

Download the file attached to the room. Unzip the compress file by using unzip gpg.zip command.

Now import the key by using following command:

gpg --import tryhackme.key

Now decrypt the message by using following command:

gpg --output message.txt --decrypt message.gpg

Pineapple

Task 12: The Future — Quantum Computers and Encryption

I understand that quantum computers affect the future of encryption. I know where to look if I want to learn more.

No answer needed