TryHackMe: Cryptography for Dummies

Why we need cryptography?

Nowadays, almost all the data we get/send over the internet is encrypted and cannot be seen in plaintext. This is all because of cryptography.

Types of cryptography

• Symmetric

Plaintext + Encryption Key → Encoded Text

• Asymmetric

Sender: Plaintext + Receiver’s Public Key → Encoded Text

Recipient: Encoded Text + Receiver’s Private Key → Plaintext

Why is asymmetric cryptography used?

For symmetric cryptography, anyone who gets hold of the encryption can encrypt and decrypt the message that you sent.

While in asymmetric cryptography, only the holder of the private key can decrypt the message.

Note : Symmetric cryptography is faster than asymmetric, but asymmetric is more secure.

#1 What type of cryptography is more secure?

asymmetric

#2 What type of cryptography is faster?

symmetric

#3 What type of cryptography will a Bank site use?

asymmetric

#4 What will you use to encrypt your messages in asymmetric cryptography?

public key

#5 What will you use to decrypt messages in asymmetric cryptography?

private key

#6 Does symmetric cryptography use two different keys for encryption/decryption? (aye/nay)

nay

What is a hash?

TryHackMe | Cryptography for Dummies

What are hashes used for?

Hash is used for file identification and storing sensitive data like password. When you create an account on a website, your password is converted into hash and stored in the database.

#1 What’s the MD5 hash of “hashes are cool”?

Use this MD5 hash generator to get the answer.

f762d32e3c160900d94b683e927555b

#2 What does MD5 stand for?

Message Digest 5

#3 Who created MD5?

Ronald Rivest

Decoding and encoding

To understand more about Base64, visit this link:

Decoding and Encoding: Base64. What is base64 | by goay xuan hui | May, 2021 | Medium

#1 Encode the string “cryptographyisuseful” with Base64

Y3J5cHRvZ3JhcGh5aXN1c2VmdWw=

#2 Decode the string “dGhlIHNlY3JldCB3b3JkIGlzIDogd2F0ZXJtZWxvbg==”. What’s the secret word?

watermelon