This scheme could be easily guessed by a dictionary attack that simply ran through combinations of dictionary words instead of individual characters.
If this became a popular scheme, the whole entropy argument goes out the door. It only has more entropy if we compare the two schemes on a character-by-character basis (~10 vs. ~25). Of course the longer string will appear to have more entropy.
But if a password guesser expects the pattern of the "four common words" scheme, as they might if it became popular, it's not nearly as entropic. A better comparison would be to consider each word as a single "character" from a 180,000 sized alphabet (for an English dictionary).
Calculate the entropy of that and you'll find it's in the same ballpark.
If you took the suggestion in your last sentence instead of offering it to the rest of us, you would see that the entire rest of your comment is incorrect.
If this became a popular scheme, the whole entropy argument goes out the door. It only has more entropy if we compare the two schemes on a character-by-character basis (~10 vs. ~25). Of course the longer string will appear to have more entropy.
But if a password guesser expects the pattern of the "four common words" scheme, as they might if it became popular, it's not nearly as entropic. A better comparison would be to consider each word as a single "character" from a 180,000 sized alphabet (for an English dictionary).
Calculate the entropy of that and you'll find it's in the same ballpark.