Code-breaking methodologies

- [Instructor] If you're going to try…attacking cryptography,…you need to have some kind of a strategy.…So we're going to talk through a couple of different strategies…for attacking cryptography.…The first is trickery and deceit,…which we often just call social engineering.…If you can trick or convince somebody…to simply give you their password,…give you their key,…that's often the easiest route in.…Things like frequency analysis can also be very useful.…So, for example, a histogram of the frequency…of letters or groups.…If you were to look at English as a language,…what you would find is, statistically, over long novels,…that E is the most common letter in the English language…used by far,…followed by T, A, and O.…

Using that knowledge, you may be able to glean…the original content of something simply based…on the frequency of how letters…or groupings of letters appear.…The next is brute force, and this is, really,…no pizazz to it, it is…just trying every possible combination.…The key length can be a big factor in this,…