They seem to be using a dictionary consisting of the 30% of words in the Brown corpus which are the most common. So a ~20k word dictionary, very small.
The study does not really tell us anything about what “law enforcement can break.” Nor does it tells us anything about “three random word” passphrases. It tells us that people who do pick a three-word passphrase often do not choose those words well and do much worse than if they had chosen them at random from a dictionary of reasonable size.
They seem to be using a dictionary consisting of the 30% of words in the Brown corpus which are the most common. So a ~20k word dictionary, very small.
The study does not really tell us anything about what “law enforcement can break.” Nor does it tells us anything about “three random word” passphrases. It tells us that people who do pick a three-word passphrase often do not choose those words well and do much worse than if they had chosen them at random from a dictionary of reasonable size.