Dailydave mailing list archives
iTunes
From: Steve Tornio <steve () vitriol net>
Date: Wed, 12 Jul 2006 05:29:46 -0500
When Dave first posed his question to the list, Blue Boar had the idea to grab the iTunes free song of the day, burn it as an audio track and generate an md5sum of the track. It seemed like a good idea to me, so I grabbed the same song from 2 different computers, with 2 different accounts, and burned them as audio tracks. My 2 files matched, but they were different from BB's, so we tried to figure out why. The difference was almost certainly due to different DVDR/CDR drives. My PowerBook and Mac Mini use SuperDrives made by Matshita, and Blue Boar's iBook has a CDRW made by Matshita. I performed the same test on a G5 with a Pioneer drive, and got yet another md5sum. Michael Spath posted to the list, "This comes from the fact that the CD-DA Red Book does not clearly specifies where audio starts, thus different drive manufacturers did implement different drive offsets (both on reading and writing)." It looks like this is the case, and generating md5s against the CD tracks will not be effective in telling us whether the files preserve any user-identifying information. So, I backed up a little bit and tried a different test. I have a song downloaded from iTunes on two different days, using two separate accounts, from two separate IP addresses. I went through the process of converting the files to MP3 (Make playlist, Add AAC-protected song to playlist, burn playlist to CD, import song from CD as MP3). I set the import settings on both computers to be identical. The resulting mp3s have identical md5sums. It doesn't seem likely that any watermarking survived the burning/ripping process. [rogue:iTunes Music/The Presets/Beams] steve% md5 01\ Girl\ and\ the\ Sea.mp3 MD5 (01 Girl and the Sea.mp3) = 3e2cc34e8a255f5487e6ace5b15242ff [rogue:iTunes Music/The Presets/Beams] steve% ls -l total 22568 -rw-r--r-- 1 steve staff 6867196 Jul 11 16:28 01 Girl and the Sea.mp3 -rw-r--r-- 1 steve staff 4684323 Jul 11 09:55 04 Girl and the Sea.m4p [rogue:iTunes Music/The Presets/Beams] steve% jrobinett04:~/Music/iTunes/iTunes Music/The Presets/Beams josh$ md5 01 \ Girl\ and\ the\ Sea.mp3 MD5 (01 Girl and the Sea.mp3) = 3e2cc34e8a255f5487e6ace5b15242ff jrobinett04:~/Music/iTunes/iTunes Music/The Presets/Beams josh$ ls -l total 22568 -rw-r--r-- 1 josh josh 6867196 Jul 11 16:33 01 Girl and the Sea.mp3 -rw-r--r-- 1 josh josh 4684328 Jul 10 15:00 04 Girl and the Sea.m4p jrobinett04:~/Music/iTunes/iTunes Music/The Presets/Beams josh$ _______________________________________________ Dailydave mailing list Dailydave () lists immunitysec com http://lists.immunitysec.com/mailman/listinfo/dailydave
Current thread:
- iTunes Steve Tornio (Jul 12)
- Re: iTunes Nicolas RUFF (Jul 13)
- Re: iTunes Steve Tornio (Jul 13)
- Re: iTunes Blue Boar (Jul 14)
- Re: iTunes Steve Tornio (Jul 13)
- Re: iTunes Nicolas RUFF (Jul 13)