Comment Re:ObXKCD: Passphrases (Score 1) 288
"To what extent can xkcd be credited?" Not a great extent. Most of us knew the math already
There is a difference between knowing the math and applying it. A nice, easy to remember story can make that difference.
but it only works well when you really select randomly from a dictionary instead of making grammatically correct sentences
Grammatically correct is not that much of a reduction in key space. I would imagine that "Adjective" "Noun" "Transitive verb" "Adjective" "Noun" yields a larger keyphrase than four random words, and it is probably easier to remember than "Noun" "Noun" "Adjective" "Noun", even for rare words.