How Does Encryption Work?

Video Transcript

"Hi, my name's Dave Andrews and today I'm going to show you a little bit about how encryption works. Now what I'm going to show you is called a cypher, which is one of the simpler forms of encryption. It's actually, you know, can be dated to around Roman times and possibly even before that. So I'm going to pull up My Computer here and show you how cyphers work. So I have here a text document and as you can see I have all the letters of the alphabet typed out here, as well as the number for which those letters fall on. And then on the last row I have other characters that we're going to use to represent those letters. Now, a cypher simply takes text and takes every single character and represents that character with another character. And the response that you get is your cyphered text. So I'm going to take "This is fun" and I'm going to run it through my cypher here. I have a "t" which corresponds to the letter "b" in my cypher. I then have an "h" which corresponds to a star. An "i" is an opening parenthesis and an "s" is an "a". Then there's a space. An "i" is an opening parenthesis. A "s" is an "a". And an "f" is a carrot mark. A "u" corresponds to the "c". And the letter "n" corresponds to a forward leaning slash. So as you can see, this line right here is our encrypted text, "This is fun". The way you decrypt that text is to run it through your cypher backwards. In other words, we'll take the "b" and correspond it upwards instead of going downwards. So our letter "b" is a "t". Our star is an "h". Our opening parenthesis is an "i". The letter "a" is an "s". Then there's a space. Opening parenthesis is an "i". The letter "a" is an "s", space. A carrot is an "f". The letter "c" is a "u". And the forward leaning slash is an "n". So we have just decrypted our text by running it through the cypher backwards. And, you know, there are alot more complicated methods of encryption but this is a good way to get your mind wrapped around how encryption works. My name's Dave Andrews and I've just showed you how encryption works."