On Mon, Apr 28, 2008 at 12:44:10AM +0300, Shachar Shemesh wrote: > o Using the later, I find it hard to believe that it > actually provides rsync friendliness. In particular, > does it provide rsync friendliness if the change (not at > the end of the file) caused a modification to the file > size?
OK, here's what I did: dd if=/dev/zero of=test_long1 bs=1M count=16 dd if=/dev/urandom of=test_rand_1m bs=1M count=1 cat test_long1 test_rand_1m >test_long2 cat test_rand_1m test_long1 >test_long3 cat test_rand_1m test_long1 test_rand_1m >test_long4 Then I unmounted. Then I figured out which was which by file size, more or less: -rw-r--r-- 1 rlpowell users 16777216 2008-04-27 17:06 SfNM,dlfBajg2NiV0YzRJQz4 -rw-r--r-- 1 rlpowell users 17825792 2008-04-27 17:38 NZ92YbAoRtXWp29DypUz6g,n -rw-r--r-- 1 rlpowell users 17825792 2008-04-27 17:38 3XnzDYA9ebc1ZNTuxQjsyVw8 -rw-r--r-- 1 rlpowell users 18874368 2008-04-27 17:38 X3bNiy35p439CRPql54uJ7I9 cp SfNM,dlfBajg2NiV0YzRJQz4 /tmp/target rsync --stats --no-whole-file NZ92YbAoRtXWp29DypUz6g,n /tmp/target [snip] sent 1065173 bytes received 24607 bytes 726520.00 bytes/sec total size is 17825792 speedup is 16.36 cp SfNM,dlfBajg2NiV0YzRJQz4 /tmp/target rsync --stats --no-whole-file 3XnzDYA9ebc1ZNTuxQjsyVw8 /tmp/target [snip] sent 2112853 bytes received 24607 bytes 854984.00 bytes/sec total size is 17825792 speedup is 8.34 cp SfNM,dlfBajg2NiV0YzRJQz4 /tmp/target rsync --stats --no-whole-file X3bNiy35p439CRPql54uJ7I9 /tmp/target [snip] sent 3161557 bytes received 24607 bytes 6372328.00 bytes/sec total size is 18874368 speedup is 5.92 So yeah, it appears to work. If you want me to test something else, let me know. It's worth noting that I prioritized rsyncability over security in my setup; I used block encoding, and no IV at all. > * I have not looked at the actual implementation, only at the > presentation, but it seems to me that the "stream mode" offers > grave security issues if an attacker ever has access to the > same encrypted image before and after a modification that > changes the file length. This is unrelated to rsyncrypto. This > is, by the way, an issue with many file encrypting programs. Stream mode only affects files names, AFAICT. -Robin -- Lojban Reason #17: http://en.wikipedia.org/wiki/Buffalo_buffalo Proud Supporter of the Singularity Institute - http://singinst.org/ http://www.digitalkingdom.org/~rlpowell/ *** http://www.lojban.org/ ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Rsyncrypto-devel mailing list Rsyncrypto-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rsyncrypto-devel
