[Oct 1st Blog]

     The strength of a cryptographic algorithm depends upon several factors. Of course, these algorithms all depend upon a computer's favorite food: math. Now, imagine you are back in your high school math class. The first problem you solve is quite easy, because all you need to do is plug in the given numbers into a formula. However, as you continue solving problems, you realize the answers you're getting aren't making any sense. You can't just use the same old formula again; each problem requires you to derive a new formula in order to solve it. This unpredictability strips you of your shortcut method towards solving a problem. This is the utility of random numbers -- numbers which all have an equal probability of being selected. Suddenly a nefarious hacker thinks she's cracked an algorithm at last, yet the algorithm is being regenerated randomly, leaving the hacker to drown in a sinking pit of cleartext. Perhaps you don't think about this too much, but being built on a plethora of complex algorithms leaves computers to be pathetically bad at being random -- almost as bad as yourself! So many computer randomly-generated numbers are created by PRNG (psuedorandom number generator), which is basically like a computer pretending to be like some non-existent random-number machine.

    Forget PRNG for a minute -- hackers have grown too smart for that basic stuff. If you REALLY want to make your data secure, you need to use factors that make your algorithm even stronger. One such factor is diffusion, where a single change in plaintext changes multiple characters in ciphertext. Let's go back to the hacker from before. Imagine she's cracked through one of your algorithms and is feeling reinvigorated. However, when she goes to decrypt your plaintext, she sees that multiple characters of ciphertext are needed, at random, to find just one bit of output. Or, another factor which can be used is confusion, in which the ciphertext itself is made out of multiple parts of the key. This is like having to find out which combination of 5 formulas were used in what order when all you have is the final answers. Now, the hacker has to go find out the entire key before she can cryptoanalyse your ciphertext.