The concept of encryption can be quite daunting when you first look at it, however the basic concept of encryption is not that hard to understand
When I moved into my house, my bathroom door didn’t have a key. The previous owners of the house didn’t know what key was needed for that door as they never had one either.
I went down to my local hardware store and spoke to them about my problem, and after paying a deposit for a whole set of keys, I was on my way back home.
The key set they gave me was for the Y-standard (each key starts with Y, i.e. Y1, Y2, Y3 etc), and there were just over a hundred of these keys. So there I was, in my bathroom trying every key in the bunch starting at Y1 all the way through to the end. Now if it had been my lucky day, I would have tried Y1 and had success. Worst case scenario it would have been the very last key, which I think was Y115. Now with only about 115 keys to try, it really isn’t the end of the world, and I did manage to find the right one after some time.
The point to my scenario, is that no-one had to explain to me how to use a key, or how to unlock a door. That’s not a big secret to anyone. The big secret is, which key opens the door.
Similarly with encryption, the algorithm that is used to encrypt and decrypt data is freely available on the internet, if you were to do a couple searches you will find the equation used in particular formula – much like different doors have different types of locks.
The big difference between my bathroom door, and computer encryption, is the amount of keys in the bunch.
If we were to assume that there was such a thing as 3-bit encryption, then the possible keys would be
Giving us 8 possible keys to try (2 to the power of 3). Needless to say, with only 8 keys this would take no time at all to find the right one to “open our door”
Encryption technologies therefore use a much larger structure, and hence have a lot more keys that one would have to try to break into an encrypted document.
40-bit encryption (2 to the power of 40) gives us a total of 1,099,511,627,776 – That’s over a TRILLION possibilities, and it’s a good thing that my bathroom door didn’t have that many keys I had to try! But just how good is that? Considering that in human terms a trillion of anything is amazing. Computers however are able to do millions and billions of things per second. My computer for example, is able to test just over 10 million keys per second, which makes a trillion not that far out of reach. Based on that, it would take my machine 1.2 Days to crack a 40-bit encryption standard.
So how good is 56-bit encryption then?
56-bit will give us a total of 72,057,594,037,927,936 (72 Quadrillion keys!!!) I can’t even comprehend that amount of anything. But yet again, just how good is that really. Well based on my computer been able to do just over 10 million keys per second, it would take my computer 228 YEARS!!!! The beautiful thing about binary, is that for every bit larger the encryption key is, the amount of keys DOUBLES in size. So 57-bit would take me 456 Years, 58-bit would take me 912 Years etc.
The good news is, that encryption standards today usually work on
56-bit 72,057,594,037,927,936 (228 years for my computer to decrypt)
64-bit 18,446,744,073,709,551,616 (58,494 Years)