Real-world exploits

- [Instructor] Now, there are a lot of strategies…for attacking cryptography, and you'd think…because there are so many strategies for attacking it,…that it must be relatively easy to break, right?…Well, it's actually quite the opposite.…When cryptography is done right,…it's actually very hard to break.…And one of the really key differentiators…that decides how hard it is to break cryptography…is the key length.…Recall, a simple key of 256 bits…can actually count up to one times e to the power 77.…It is a very large key space.…So here's some examples of attacks on cryptography…that have actually happened.…

So Distributed.net built what they call…these RC hacking challenges.…So first they did a challenge…where they were attempting to crack an RC5-56 bit.…They did this by using 26,000 processors…and it took them 250 days to crack it.…So next they attempted to crack RC5-64 bit.…Using 331 processors,…it took 1,700 days for them to crack.…Next, they moved on to attempting to crack RC5-72 bit.…And just to show that by adding only eight more bits…