Crucial Crypto Math

There's a little bit of math(s) that comes up relatively often in cryptography. The Modulo operator. Pretty much every programming language implements this operator, or has it available through a library. When you need to work with large numbers, use a programming language. Python is good for this as integers are unlimited in size, and you can easily get an interpreter.

Examples

25 % 5 = 0 (5*5 = 25 so it divides exactly with no remainder)

23 % 6 = 5 (23 does not divide evenly by 6, there would be a remainder of 5)

An important thing to remember about modulo is that it’s not reversible. If I gave you an equation: x % 5 = 4, there are infinite values of x that will be valid.