Hidden inside a simple color-mixing analogy is one of the most elegant ideas in cryptography, a mathematical trap door that lets two strangers build a shared secret in plain sight. This is the story ...

You may never have heard of modular arithmetic, but you use it every day without the slightest difficulty. In this system, numbers wrap around when they reach a certain size called the modulus; it is ...

One of my fellow contributors here recently wrote a post about leap years and why we have them. This reminded me of modular arithmetic and the formula for calculating the day of the week for any date ...