Note:
- The questions are shortened for a cleaner view
- Questions that are straightforward will only have answers attached. Such questions can be easily answered by reading the documentation given in the room.
Task 1 - Introduction#
No answer needed
Task 2 - Importance of Cryptography#
1) Standard required for handling credit card information?#
Ans: Lock
Task 3 - RSA#
1) Knowing that p = 4391 and q = 6659. What is n?#
n = p x q
Ans: 29239669
2) Knowing that p = 4391 and q = 6659. What is ϕ(n)?#
ϕ(n) = n - p - q + 1
Ans: 29228620
Task 4 - Diffie-Hellman Key Exchange#
1) Consider p = 29, g = 5, a = 12. What is A?#
A = g^a mod p
Ans: 7
2) Consider p = 29, g = 5, b = 17. What is B?#
B = g^b mod p
Ans: 9
3) What is the key calculated by Bob?#
key = B^a mod p
Ans: 24
4) what is the key calculated by Alice?#
key = A^b mod p
Ans: 24
Task 5 - SSH#
1) What algorithm does the key use?#
We can ls the directory and the type is in the name of they key.
Ans: RSA
Task 6 - Digital Signatures and Certificates#
1) What does a remote web server use to prove itself to the client?#
Ans: Certificate
2) What would you use to get a free TLS certificate for your website?#
Ans: Let's Encrypt
Task 7 - PGP and GPG#
1) What secret word does the message hold?#
We first import the key and the decrypt the message.
user@ip-10-48-173-106:~/Public-Crypto-Basics/Task-7$ ls
message.gpg tryhackme.key
user@ip-10-48-173-106:~/Public-Crypto-Basics/Task-7$ gpg --import tryhackme.key
gpg: /home/user/.gnupg/trustdb.gpg: trustdb created
gpg: key FFA4B5252BAEB2E6: public key "TryHackMe (Example Key)" imported
gpg: key FFA4B5252BAEB2E6: secret key imported
gpg: Total number processed: 1
gpg: imported: 1
gpg: secret keys read: 1
gpg: secret keys imported: 1
user@ip-10-48-173-106:~/Public-Crypto-Basics/Task-7$ gpg --decrypt message.gpg
gpg: encrypted with rsa1024 key, ID 2A0A5FDC5081B1C5, created 2020-06-30
"TryHackMe (Example Key)"
You decrypted the file!
The secret word is Pineapple.
Ans: Pineapple
