Practical Cryptography in Python

Develop a greater intuition for the proper use of cryptography. This book demystifies cryptographic internals and teaches you how to write basic cryptographic algorithms in Python.

Cryptography is the life blood 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
  
• Generate hashes in Python: recommended algorithms and why SHA-1 is being retired
  
• Know what block ciphers are used for and their basic properties
  
• Encrypt with AES in Python: recommended algorithms and modes, and what can go wrong
  
• Know what public keys and private keys are used for and their basic properties, and how the security of an algorithm depends on parameters such as padding
  
• Provide message integrity and digital signatures using keyed hashes and asymmetric cryptography; know how a certificate differs from a key, and why it matters
  
• Securely generate a shared symmetric session key using asymmetric encryption
• Use modern symmetric ciphers such as AES-GCM and CHACHA
  
• Utilize TLC connections and modern technologies 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.