"These results reflect the fact that dictionary checks appear to contribute heavily to reducing usability by making password creation difficult. To some extent,

"These results reflect the fact that dictionary checks appear to contribute heavily to reducing usability by making password creation difficult. To some extent, this may be a result of our harsh check that uses a cracking dictionary and matches words of any length, rather than ignoring words of less than three or four letters, as may be more typical. We believe, however, that what makes any dictionary check valuable - preventing the use of common or predictable letter strings in passwords—also makes it inherently more difficult for users to think of a valid password. An interface that more clearly explains to users why their passwords are being rejected and provides suggestions for avoiding future rejections might help to reduce frustration" https://users.ece.cmu.edu/~lbauer/papers/2011/chi2011-passwords.pdf https://users.ece.cmu.edu/~lbauer/papers/2011/chi2011-passwo...