Book Image

Demystifying Cryptography with OpenSSL 3.0

By : Alexei Khlebnikov
Book Image

Demystifying Cryptography with OpenSSL 3.0

By: Alexei Khlebnikov

Overview of this book

Security and networking are essential features of software today. The modern internet is full of worms, Trojan horses, men-in-the-middle, and other threats. This is why maintaining security is more important than ever. OpenSSL is one of the most widely used and essential open source projects on the internet for this purpose. If you are a software developer, system administrator, network security engineer, or DevOps specialist, you’ve probably stumbled upon this toolset in the past – but how do you make the most out of it? With the help of this book, you will learn the most important features of OpenSSL, and gain insight into its full potential. This book contains step-by-step explanations of essential cryptography and network security concepts, as well as practical examples illustrating the usage of those concepts. You’ll start by learning the basics, such as how to perform symmetric encryption and calculate message digests. Next, you will discover more about cryptography: MAC and HMAC, public and private keys, and digital signatures. As you progress, you will explore best practices for using X.509 certificates, public key infrastructure, and TLS connections. By the end of this book, you’ll be able to use the most popular features of OpenSSL, allowing you to implement cryptography and TLS in your applications and network infrastructure.
Table of Contents (20 chapters)
Part 1: Introduction
Part 2: Symmetric Cryptography
Part 3: Asymmetric Cryptography and Certificates
Part 4: TLS Connections and Secure Communication
Part 5: Running a Mini-CA

What is a key derivation function?

A Key Derivation Function (KDF) is a function that derives a secret key of the desired bit length from some other secret material, such as a password, a passphrase, another shared secret, or a combination of asymmetric private and public keys. That other secret material is also called Input Key Material (IKM), while the secret key produced is also called Output Key Material (OKM). IKM and OKM often have different lengths. A KDF typically uses a cryptographic hash function or block cipher operations under the hood.

A Password-Based Key Derivation Function (PBKDF) is a KDF designed to produce secret keys from low-entropy IKMs, such as passwords. Those secret keys can be used as symmetric encryption keys. Another popular application of PBKDFs is password hashing. PBKDFs provide more brute-force-resistant password hashing than cryptographic hash functions alone.

Some key derivation functions are used for key exchange in secure network protocols...