Back-of-napkin thoughts prompted by https://twitter.com/soapko/statuses/233009083446349825
3-second song clip, in taps
Say the typical song is 120 BPM.
( 120BPM / 60s = 2 beats per second) * 3 seconds = 6 beats (quarter-notes)
Biggest assumption is that 6 beats in 3 seconds @ sixteenth note resolution = 24 available notes of resolution
3 possible states per note: attack, sustain, rest.
3^24 = 282,429,536,481 possible combinations
12 case-sensitive alphanumeric characters
62 ^ 12 = 3,226,266,762,397,899,821,056 possible combinations
Passphrase has 11,423,262,604x more possibilities