TryHackMe — Cryptography Basics | Cyber Security 101 (THM)

Importance of Cryptography

Cryptography ensures secure communication, maintaining data confidentiality, integrity, and authenticity in the presence of adversaries. You rely on cryptography daily:

• Login: Your credentials are encrypted, preventing unauthorized access.
• SSH: Encrypted tunnels protect your session from eavesdropping.
• Online Banking: Cryptography verifies the server’s authenticity.
• Downloads: Hash functions check file integrity.

Cryptography is fundamental for standards like PCI DSS for credit card data and HIPAA/GDPR for medical records, establishing necessary security without direct user interaction.

Questions and Answers

1. What is the standard required for handling credit card information?

• PCI DSS

Plaintext to Ciphertext

Plaintext is readable data, like text or images, before encryption. Using a cipher (encryption algorithm) and a key, plaintext is transformed into ciphertext, the unreadable, scrambled output. To revert it back to plaintext, we pass the ciphertext and key through the decryption process.

Key terms:

• Plaintext: Original, readable data.
• Ciphertext: Encrypted, unreadable data.
• Cipher: Algorithm for encryption and decryption.