In 1854, Sir Charles Wheatstone invented the cipher known as "Playfair," named for his friend Lyon Playfair, first Baron Playfair of St. Andrews, who popularized and promoted the cipher. Its ...

Introduction to ciphers and substitution. Alice and Bob and Carl and Julius: terminology and Caesar Cipher ; The key to the matter: generalizing the Caesar Cipher ; Multiplicative ciphers ; Affine ...

You can make a message secret in countless different ways. One common way is to use a substitution cipher, in which one letter is substituted for another. Another is to employ a transposition cipher, ...

Learn how to implement a classic substitution cipher in C! This step-by-step tutorial walks you through encoding and decoding messages by replacing each letter with another according to a fixed key. A ...

ROT13, a decades-old letter substitution cipher, is changing the way people discuss spoilers on social media. The cipher, which simply shifts each letter 13 places in the alphabet, turns spoilers into ...

Threat actors in the phishing business have adopted a new technique to obfuscate the source code for the forged page by using a custom web font to implement a substitution cipher that looks like ...