Cyber Ops Associate Course: Module 21 - Cryptography

Overview

• Focus on skills and knowledge for a security analyst at a Security Operations Center (SOC).
• Prepares for Cisco 200-201 certification.
• Module 21 covers cryptography.

Key Topics

• Asymmetric Keys
• Public Key Infrastructure (PKI)
• Integrity, Authenticity, Confidentiality
• Public Key Cryptography
• Applications and Impacts of Cryptography

Importance of Cryptography

• Key elements: Integrity, Authenticity, Confidentiality

Integrity and Authenticity

• Elements:
  • Data Integrity
  • Original Authentication
  • Data Confidentiality
  • Data Non-repudiation
• Guarantees message hasn't been altered, is genuine, only authorized access, and cannot be denied by sender.

Cryptographic Systems

Hashing Functions

• Converts plaintext to a fixed-length hash value.
• Mathematical one-way function.
• Infeasible for two different messages to have the same hash value.
• Common algorithms: MD5, SHA (SHA-1, SHA-2, SHA-3)

Hashing Algorithm Comparison

• MD5: 128-bit, not secure.
• SHA-1: 160-bit, slow, weak.
• SHA-2: 256/512-bit, more secure.

Purpose of Hashing

• Detects changes or tampering.
• Vulnerable to man-in-the-middle attacks.

HMAC (Hashed Message Authentication Code)

• Combines hashing with a secret key.
• Ensures integrity and authenticity.

Data Confidentiality

• Types of Encryption:
  • Symmetric: Same key for encryption and decryption (e.g., DES, AES).
  • Asymmetric: Different keys for encryption and decryption (e.g., RSA, PKI).

Symmetric Key Encryption

• Pre-shared key, faster, used for bulk encryption (e.g., VPNs).
• Block vs. Stream Ciphers.

Asymmetric Key Encryption

• Uses public and private keys.
• Slower, used for secure communications (e.g., HTTPS).

Combining Encryption Techniques

• Achieves both confidentiality and authentication.

Diffie-Hellman Key Exchange

• Asymmetric algorithm for creating a shared secret without precommunication.

Public Key Cryptography

• Digital Signatures: Ensure authenticity, integrity, non-repudiation.
• Applications: Digital certificates, code signing.

Certificate Authorities (CA) and PKI Trust

• Role of CA: Issues and manages digital certificates.
• Certificate Hierarchies:
  • Single root, hierarchical, cross-certified.
• Certificate Classes: Range from 0 (testing) to 5 (government security).

PKI Topologies

• Single Root, Cross Certified, Hierarchical.

PKI Interoperability

• RFC 2527 outlines PKI standards.

Applications and Impact of Cryptography

• Used in SSL/TLS, HTTPS, VPNs, secure emails, etc.
• Important for network security.
• Dynamic field with changing algorithms.

Summary

• Recap on elements of cryptography, types of encryption, PKI systems.
• Importance of understanding cryptographic protocols for security analysts.

Final Notes

• Communication and discussion are encouraged for better understanding and retention.
• Open for questions and further clarification.