Practical Cryptography in Python

Develop a greater intuition for the proper use of cryptography. This book teaches the basics of writing cryptographic algorithms in Python, demystifies cryptographic internals, and demonstrates common ways cryptography is used incorrectly.

Cryptography is the lifeblood of the digital world’s security infrastructure. From governments around the world to the average consumer, most communications are protected in some form or another by cryptography. These days, even Google searches are encrypted. Despite its ubiquity, cryptography is easy to misconfigure, misuse, and misunderstand.

Developers building cryptographic operations into their applications are not typically experts in the subject, and may not fully grasp the implication of different algorithms, modes, and other parameters. The concepts in this book are largely taught by example, including incorrect uses of cryptography and how "bad" cryptography can be broken. By digging into the guts of cryptography, you can experience what works, what doesn't, and why.

What You’ll Learn

• Understand where cryptography is used, why, and how it gets misused
• Know what secure hashing is used for and its basic properties
• Get up to speed on algorithms and modes for block ciphers such as AES, and see how bad configurations break
• Use message integrity and/or digital signatures to protect messages
• Utilize modern symmetric ciphers such as AES-GCM and CHACHA
• Practice the basics of public key cryptography, including ECDSA signatures
• Discover how RSA encryption can be broken if insecure padding is used
• Employ TLS connections for secure communications
• Find out how certificates work and modern improvements such as certificate pinning and certificate transparency (CT) logs

Who This Book Is For

IT administrators and software developers familiar with Python. Although readers may have some knowledge of cryptography, the book assumes that the reader is starting from scratch. 

Table of contents

Cryptography: More Than Secrecy

Hashing

Symmetric Encryption: Two Sides, One Key

Asymmetric Encryption: Public/Private Keys

Message Integrity, Signatures, and Certificates

Combining Asymmetric and Symmetric Algorithms

More Symmetric Crypto: Authenticated Encryption and Kerberos

TLS Communications