> Everyone knows a verse from a song or a passage from a book These do definitely don't have the 1.0 to 1.9 bits of entropy the paper you posted is talking abo

> Everyone knows a verse from a song or a passage from a book These do definitely don't have the 1.0 to 1.9 bits of entropy the paper you posted is talking about. If what you're suggesting were to be "best practice" attackers would try, say, the 1 million most famous songs and the 1 million most famous books and take every sentence/verse from, say, the starting word of every sentence/verse up to 3 to 8 words. This would be, what, very ballpark, a 34 to 36 bits keyspace? Known text doesn't make for a good passphrase source.