So I have been looking online for how encrytion works, I get how cyphers work, what I want to know is what dose the bit rating mean in relation to the amount of security it provides. For example lets take some imaginary algorithm that is offered in both 64 and 128 bit versions, the 128 is more secure but I want to know why? Also how long would it take say a 3ghz intel to crack it? I have searched both google and these forums and come up with pretty much everything aside from this answer, any help?