# Module Overview

This module focuses on practical aspects of private key and public key cryptography. It describes the mechanisms/algorithms that cryptography provides for symmetric and asymmetric encryption, key agreement, hashing, and digital signatures and elaborates on how they are used to achieve the major pillars of information security including confidentiality, integrity, authenticity, and non-repudiation. It discusses the limitations of these mechanisms/algorithms and emphasizes the need for each of them. It also includes a discussion of the need for a PKI (public key infrastructure) and explains how digital certificates and certification authorities are used to provide authentication.

The module is divided into 4 submodules:

- Symmetric Key Cryptopgraphy
- Public Key Cryptography
- Hash functions
- Digital Signatures and PKI

Learning objectives for this module and the tasks you need to complete in this module are listed below. Along with each task you need to complete, the module learning objectives (MLOs) that it aligns with are indicated in parentheses at the end of the item.

## Module Learning Objectives

By the end of this module you should be able to:

1. Define encryption, decryption, plain text, cipher text, and can explain their role in cryptography.
2. Use classical cipher methods such as Caesar cipher and substitution cipher to encrypt/decrypt data by hand.
3. Compare and contrast symmetric and asymmetric encryption.
4. Identify well-known algorithms of symmetric and asymmetric encryption.
5. Explain the use of hash functions in securing information.
6. Explain the use of digital signatures in securing information.
7. Explain the role of digital certificates and certificate authorities in secure communications.
8. Utilize tools to demonstrate how public key and symmetric key cryptography work.
9. Utilize tools to demonstrate how hashing works.

## Task List

The tasks included in this module are:

1. Symmetric Cryptography (ppt) | MLO1, MLO2, MLO4
   Public key cryptography (ppt) | MLO3, MLO4,
   Hash functions (ppt) | MLO5
   Digital signatures (ppt) | MLO6, MLO7
   LM Hashes (website reading) | MLO5
   Digital signatures and certificates (website reading) | MLO6, MLO7
   Lab 4 - Decrypting classical ciphers | MLO2
   Lab 5 - Importance of data security | MLO8
   Public key repository | MLO8
   Response to instructor | MLO8
   Lab 6 - Using public key algorithms | MLO8
   Lab 7 - Verfiying integrity of a download | MLO9
   Quiz 4, Quiz 5 | MLO1, MLO2, MLO3, MLO4, MLO5, MLO6, MLO7