Cryptography: Crypto 101

Crypto is math. Hard Math. Its very difficult to explain in details. Trust me, Im very good with words and even this is difficult for me. So here are the Cliffnotes, basically.Some kinds of mathematical functions are really easy to do in one direction and hard to do in the other direction. Its easy to multiply large primes, making one big prime number. Its really, really hard to take any given giant number and figure out which primes multiply together to give you that number. That means if you can come up with a way of scrambling something based on multiplying large primes, unscrambling it without knowing those primes will be hard. Wicked hard. Like, a trillion years of all the computers ever invented working 24/7 wont be able to do it.
There are four parts to any crypto message: the original message, called "cleartext". The scrambled message, called the "ciphertext". The scrambling system, called the "cipher". And finally there's the key: secret stuff you feed into the cipher along with the cleartext to make ciphertext. Now, of course any TG would know this, but its an updated version of cryptography. Let it rip!