Symmetric Cryptography Essential Training

Course details

If you work with computers, you use cryptography. Symmetric cryptography is a common method that uses the same key for encryption and decryption of data. Faster and less resource-intensive than asymmetric cryptography, symmetric cryptography is important for all IT professionals to understand. This course delivers a practical overview of the technology, emphasizing high-level concepts that affect how our data is stored and transmitted. Jeremy Hansen explains the difference between single key (symmetric) and multiple key (asymmetric) algorithms, and shows how symmetric encryption affects underlying binary data. Learn about the basic ciphers used in symmetric cryptography, including substitution, permutation, and transposition, and influential symmetric-key algorithms like the Advanced Encryption Standard and its predecessor, the Data Encryption Standard. Review modern block cipher modes like cipher block chaining (CBC), cipher feedback (CFB), and counter (CTR), which can help secure large amounts of data.

Learning objectives
Explain the role of encryption in modern security systems.
Explain the difference between one-key (symmetric) and multiple-key (asymmetric) algorithms.
Identify historical cryptographic algorithms.
Demonstrate the difference between block and stream ciphers.
Describe several methods that block ciphers use to encrypt and decrypt data.
Enumerate and describe several modern and recent block and stream cipher algorithms.

Concepts

0. Introduction

01 - Cryptography is everywhere
02 - Basic terminology
03 - Intro to Codespaces

1. Symmetric Cryptography Overview

04 - Cryptography's role
05 - Kerckhoffs's principle
06 - Symmetric keys
07 - Block vs. stream ciphers
08 - Cryptographic hash algorithms
09 - Challenge - Building a hash algorithm
10 - Solution - Building a hash algorithm

2. Representing and Manipulating Binary Data

11 - Binary representation
12 - Characters
13 - Integers
14 - Floating point numbers
15 - Boolean operations
16 - Padding
17 - Challenge - QR code printer
18 - Solution - QR code printer

3. Fundamental Algorithms and Components

19 - Simple substitution ciphers
20 - Polyalphabetic substitution ciphers
21 - Permutation and transposition ciphers
22 - Simple one-time pads with XOR
23 - S-boxes and P-boxes
24 - Feistel networks
25 - Linear-feedback shift registers (LFSRs)
26 - Challenge - Software-based LFSR
27 - Solution - Software-based LFSR

4. Symmetric Algorithms

28 - The Data Encryption Standard (DES)
29 - The Advanced Encryption Standard (AES)
30 - AES and DES in practice
31 - The RC4 stream cipher
32 - Challenge - Encrypting, decrypting, and hashing with OpenSSL
33 - Solution - Encrypting, decrypting, and hashing with OpenSSL

5. Block Cipher Modes

34 - Introduction to block cipher modes
35 - Cipher block chaining (CBC)
36 - CFB - Cipher feedback
37 - OFB - Output feedback
38 - CTR - Counter mode
39 - Challenge - Building a block cipher with CBC mode
40 - Solution - Building a block cipher with CBC mode

6. Keys and a Little Asymmetry

41 - Exchanging keys
42 - Key length and large numbers
43 - The importance of randomness to cryptography
44 - Modular arithmetic
45 - Diffie Hellman key exchange
46 - Challenge - Implementing Diffie Hellman
47 - Solution - Implementing Diffie Hellman

Conclusion

48 - Next steps