AES128 v AES256 encryption – What’s the difference?

Practically nothing!

It is true that a 256 bit encryption key is many times more difficult to guess (referred to as a brute force attack) than a 128 bit key. However, given that a 128 bit key takes so long to guess using such a huge amount of computing power, that for all practical purposes, it simply wouldn’t happen, how much more certain does anyone really need to be?  For an explanation of the maths try this blog

To generate this kind of brute force, a hacker would need quantum computing, which is still years away.

So, if there is practically no difference between the two in terms of ability to protect your data, are there other factors to consider?  256 bit keys require more processing power, and can take longer to execute, so on small devices where power is an issue, or where latency is likely to be an issue, users are better off with 128 bit keys.

When looking to access a system, hackers will always go for the weakest point, which isn’t going to be the encryption whether it’s a 128 bit key or a 256 bit key. Therefore, it is more important to check that the software you are considering does what you want it to do, it protects your data in the way you think it does, and that there are no weaknesses in the processes.  Also, that there are no grey areas where you are not quite sure where your data is, or who is looking after it (for example, if data is held in the cloud – do you know where the cloud actually is?).   And most important of all, the security software you choose should be easy to use, invisible to users, so that they have no need or inclination to take insecure workarounds in order to do their day to day job.

In short, don’t waste time stressing about 128 v 256 bit encryption keys.  Both do the job, and there are more important security issues to be worried about.