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Cryptography Basics
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Cryptography Basics

·2 mins·
Mahir
Author
Mahir
I poke at code, dig into security, and write down whatever I learn along the way.
Table of Contents

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
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No answer needed


Task 2 - Common Use of Asymmetric Encryption
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1) what real object is analogous to the public key?
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Ans: PCI DSS


Task 3 - Plaintext to Ciphertext
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1) What do you call the encrypted plaintext?
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Ans: ciphertext

2) What do you call the process that returns the plaintext?
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Ans: decryption


Task 4 - Historical Ciphers
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1) XRPCTCRGNEI - Caesar Cipher, what is the plaintext?
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To decrypt this we can bruteforce multiple key shifts to the left. The one that works is 15. That is key = 15.

Ans: ICANENCRYPT


Task 5 - Types of Encryption
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1) Should you trust DES? (Yea/Nay)?
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Ans: Nay

DES was adopted as a standard in 1977 and uses a 56-bit key. With the advancement in computing power, in 1999, a DES key was successfully broken in less than 24 hours, motivating the shift to 3DES.

2) When was AES adopted as an encryption standard?
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Ans: 2001


Task 6 - Basic Math
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1) What’s 1001 ⊕ 1010?
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Follow the basic rules of XOR and apply it to numbers individually.

Ans: 0011

2) What’s 118613842%9091?
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Its best to use an online python compiler. It makes calculation easier.

print(118613842%9091)

Ans: 3565

3) What’s 60%12?
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Its best to use an online python compiler. It makes calculation easier.

print(60%12)

Ans: 0

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