This list consists of ~25 tutorials to learn cryptography. You can think of this list as a "Free Online Nano Book". You'll learn cryptographic algorithms, including those currently in use such as the RSA algorithm (used for secure digital communication) and Digital Signatures Algorithm (used for digital signatures). Everything is 100% free.

This list starts out by describing what cryptography is, its various applications, branches and types of algorithms. Then, we'll see some simple encryption techniques (doesn't require any background in number theory) such as Caesar Cipher and Playfair Cipher. In sections 3 and 4, we will take a detailed look at modern cryptography algorithms for secure communication (including the required mathematics and number theory background). In section 5, we will look at other applications of cryptography such as random number generation, hash functions and password salting. In the last (bonus) section, we'll discuss human behavioral aspects of computer security and famous unsolved cryptography puzzles (including hidden treasures and unsolved murders!)

*Other versions*: Learn Cryptography in 2 weeks is a less comprehensive version with ~15 tutorials instead of ~25 (this list is a superset). Modern Cryptography: From Beginner to Expert is another version which focuses on modern cryptography only (again, ~15 tutorials instead of ~25, this list is a superset).

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