You'd be surprised at how quickly common phrases are compromised. According to [1], a 6 word phrase, "it was the best of times", albeit unmodified, was broken i

You'd be surprised at how quickly common phrases are compromised. According to [1], a 6 word phrase, "it was the best of times", albeit unmodified, was broken in 4 seconds. A less common phrase, "You stay classy San Diego", was never compromised. So there may be some security in a combination of common phrases and modifier patterns, but I would say it's not enough for highly sensitive accounts. 1. http://www.reddit.com/r/Bitcoin/comments/1ndsxi/a_test_of_brainwallet_passphrases/ http://www.reddit.com/r/Bitcoin/comments/1ndsxi/a_test_of_br...