Unlocking the Secrets of Cryptography with TryHackMe
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Chapter 1: Understanding Cryptography Fundamentals
In this chapter, we will explore essential encryption methods including AES, Diffie-Hellman key exchange, hashing techniques, Public Key Infrastructure (PKI), and Transport Layer Security (TLS).
The video "Introduction to Cryptography - Tryhackme" provides a foundational overview of these concepts, making it an excellent starting point for beginners.
Section 1.1: Analyzing Encrypted Messages
You have encountered the following encrypted text:
"Xjnvw lc sluxjmw jsqm wjpmcqbg jg wqcxqmnvw; xjzjmmjd lc wjpm sluxjmw jsqm bqccqm zqy." Zlwvzjxj Zpcvcol.
This message appears to be a quote attributed to Miyamoto Musashi.
To decrypt the file named quote01, which is encrypted with AES256, utilize the key s!kR3T55 with gpg. What is the third word you uncover?
- The answer is: waste.
Next, for quote02, encrypted using AES256-CBC, also apply the key s!kR3T55 with OpenSSL. What is the third word here?
- The answer is: science.
Now, decrypt quote03, which uses CAMELLIA256, again with the key s!kR3T55 via gpg. What is the third word?
- The answer is: understand.
For further assistance, the relevant directory for this task can be found on the AttackBox at /root/Rooms/cryptographyintro/task03, or you can access Task 2's file on your own machine.
Subsection 1.1.1: Key Discoveries
Bob has received a file named ciphertext_message from Alice. You can find the necessary key in the same directory. What is the first word of the original plaintext?
- The answer is: Perception.
Next, examine Bob's private RSA key. What is the last byte of p?
- The answer is: e7.
What about the last byte of q?
- The answer is: 27.
The directory for this task is located at /root/Rooms/cryptographyintro/task04 on the AttackBox, or you can use the Task 2 file.
Section 1.2: Exploring Diffie-Hellman Parameters
In the file dhparam.pem, you will find a set of Diffie-Hellman parameters. What is the size of the prime number in bits?
- The answer is: 4096.
Additionally, what is the last byte of this prime number (the least significant byte)?
- The answer is: 4f.
For this task, navigate to /root/Rooms/cryptographyintro/task05 on the AttackBox, or refer to the Task 2 file.
Chapter 2: Advanced Cryptographic Challenges
The video "TryHackMe - Introduction to Cryptography - WriteUp" delves deeper into the challenges presented in the Cryptography room, offering solutions and insights.
Continuing with our exploration, what is the SHA256 checksum for the file order.json?
- The answer is: 2c34b68669427d15f76a1c06ab941e3e6038dacdfb9209455c87519a3ef2c660.
Modify the amount in order.json from 1000 to 9000. What is the new SHA256 checksum?
- The answer is: 11faeec5edc2a2bad82ab116bbe4df0f4bc6edd96adac7150bb4e6364a238466.
Using SHA256 and the key 3RfDFz82, calculate the HMAC of order.txt.
- The answer is: c7e4de386a09ef970300243a70a444ee2a4ca62413aeaeb7097d43d2c5fac89f.
Finally, determine the size of the public key in bits.
- The answer is: 4096.
Until which year is the certificate valid?
- The answer is: 2039.
During your system audit, you discovered that the MD5 hash of the admin password is 3fc0a7acf087f549ac2b266baf94b8b1. What is the original password?
- The answer is: qwerty123.
And that concludes our exploration! Looking forward to seeing you in the next room!