You're reading from Demystifying Cryptography with OpenSSL 3.0 Discover the best techniques to enhance your network security with OpenSSL 3.0

Product type Paperback

Published in Oct 2022

Publisher Packt

ISBN-13 9781800560345

Length 342 pages

Edition 1st Edition

Languages

Tools

Wireshark

Concepts

Cryptography

Author (1):

Alexei Khlebnikov

View More author details

Table of Contents (20) Chapters

Preface

1. Part 1: Introduction

2. Chapter 1: OpenSSL and Other SSL/TLS Libraries FREE CHAPTER

3. Part 2: Symmetric Cryptography

4. Chapter 2: Symmetric Encryption and Decryption

5. Chapter 3: Message Digests

6. Chapter 4: MAC and HMAC

7. Chapter 5: Derivation of an Encryption Key from a Password

8. Part 3: Asymmetric Cryptography and Certificates

9. Chapter 6: Asymmetric Encryption and Decryption

10. Chapter 7: Digital Signatures and Their Verification

11. Chapter 8: X.509 Certificates and PKI

12. Part 4: TLS Connections and Secure Communication

13. Chapter 9: Establishing TLS Connections and Sending Data over Them

14. Chapter 10: Using X.509 Certificates in TLS

15. Chapter 11: Special Usages of TLS

16. Part 5: Running a Mini-CA

17. Chapter 12: Running a Mini-CA

18. Index

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What is a MAC?

A MAC is a short array of bits, for example, 256 bits, that authenticates a message. Message authentication means that the receiver of the message can verify that the message is coming from the stated sender and has not been changed during the transfer. In order to generate a MAC, the sender needs a message and a secret key. In order to verify the MAC, the receiver requires the message and the same secret key. A MAC is produced by a MAC function.

The difference between a MAC and a message digest is that a message digest is not protected against forgery; however, a MAC does have such protection. If both the message and its digest are transmitted over an unprotected network, an attacker can change the message and recalculate its digest so that the changed digest will match the changed message. On the other hand, if a message is transmitted with its MAC, an attacker cannot recalculate the MAC for the changed message in the same way. This is because they do not possess...