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

Overview of key derivation functions supported by OpenSSL

OpenSSL 3.0 supports several key derivation functions, but only two of them are suitable for deriving keys from passwords, namely, scrypt and PBKDF2.

PBKDF2 is a popular PBKDF, described and recommended by the PKCS #5 standard. It uses an HMAC function, such as HMAC-SHA-256, as an underlying PRF. PBKDF2 supports a tunable number of iterations and can be made computationally intensive, but not memory-intensive. In 2021, the Open Web Application Security Project (OWASP) recommended 310,000 iterations for PBKDF2 with the HMAC-SHA-256 PRF.

Scrypt is the best available choice for PBKDF in OpenSSL 3.0. Scrypt is a PBKDF that is not only computationally intensive but also memory-intensive. Scrypt uses PBKDF2 with HMAC-SHA-256 under the hood. Scrypt enables you to tune the volume of computations, memory usage, and parallelism. In 2021, OWASP recommended the following brute-force-resistant parameters for Scrypt: N=65,536, r=8,...