Cryptography

This is the second article in a series on Cryptography for the Everyday Developer. Follow along to learn the basics of modern cryptography and encryption. A cipher is only useful if it is secure. What makes a cipher secure? Let’s remember the use case for classical ciphers — keeping messages confidential. Caesar’s cipher and Vigenère’s cipher both suffer from a similar flaw, which makes them insecure and unusable for secure communication. For both ciphers, the flaw is obvious — these ciphers allow an attacker to learn how the cipher works by inspecting the ciphertext itself. This allows an eavesdropper can decrypt the message given only the ciphertext. A secure cipher, on the other hand, is one where it is not possible to learn anything about the plaintext or the cipher’s behaviour even by inspecting numerous plaintext or ciphertext messages. ...

This is the first article in a series on Cryptography for the Everyday Developer. Follow along to learn the basics of modern cryptography and encryption. The best way to begin learning about encryption is by example. And thankfully, there exist many examples of encryption throughout history that we can draw from. One of the earliest well-known examples of encryption is the Caesar Cipher, and we will begin there. The Caesar cipher is one of the oldest and simplest forms of encryption. It works by shifting each letter in your message a fixed number of positions down the alphabet. For example, with a shift of 3: ...