Ever since writing has existed, people have wanted to send secret messages to one another--and others have wanted to intercept and read them. This is the second installment of a blog series taking you ...

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 ...

Today we’re going to talk about how to keep information secret, and this isn’t a new goal. We’re going to walk you through some common encryption techniques such as the Advanced Encryption Standard ...

The Voynich manuscript has long been shorthand for the unsolved and the unknowable, a late medieval codex filled with looping glyphs that refuse to yield a single clear sentence. A new cryptologic ...

The concluding words of Unsolved! are a call to action. Craig Bauer, a US mathematician and editor-in-chief of the journal Cryptologia, ends his hefty history of cryptography by noting that even as he ...

The Zodiac’s serial killer’s 340 cipher, which couldn’t be solved for 50 years, has been cracked by a remote team of mathematicians. A remote team of three hobbyist cryptologists have solved one of ...

A puzzle game for Windows 3.1 where players must solve substitution ciphers of well-known quotes. Rescuing nuns, cracking safes, and exploring the Vatican. It's all in a day's work for Junior—sorry, ...