Shannon entropy is based on the average probability that a given string of bits will occur in a particular type of digital file. In a general-purpose communications system, that’s the right type of entropy to use, because the characteristics of the data traffic will quickly converge to the statistical averages. But in cryptography, the real concern isn’t with the average case but with the worst case.
Matthieu Bloch, an assistant professor of electrical and computer engineering at the Georgia Institute of Technology, stated in the MIT release that, “My guess is that [the paper] will show that some of them are slightly less secure than we had hoped.” He added, “But usually in the process, we’ll also figure out a way of patching them.”
