[QUOTE=iamthewalrus(:3=]
As far as I can tell, this only adds one layer of redirection that the RIAA will have to overcome in order to file a lawsuit.
When someone searches for a file, they get, from a variety of sources, a recipe full of SHA-1 hashes for the blocks they need. Then they ask for blocks that match those hashes. So, in order to sue those offering certain blocks, all they’d have to do is find the recipe that uses those blocks, then find the peers offering them.
It’s possible that someone would be able to get away with it by arguing that the block was actually used, in his own cache, as part of some innocuous file, but I doubt it. For one, that would require a judge that could follow the math. But, more importantly, it would require actually going to trial, which very few people can afford anyway. The whole point of these lawsuits is to collect a few grand in settlement and move on.
Someone in a digg comment I was readon on the story mentioned that “solutions” like these arise because people think that the law is written like computer code, and all you have to do is find an action that won’t trip a specific definition. But that’s obviously false. The fact that the law treats certain numbers differently than other numbers is interesting to think about intellectually, but xor isn’t the magic key to legal invulnerability.
On another note, I think that a network of this type would be trivially easy to pollute, probably to the extent of complete unusability. Just introduce some hash collisions for a few blocks, and all kinds of shit goes all screwy. Given the obfuscation required, the system seems designed so that a single failure can corrupt huge amounts of data.
[/QUOTE]
Thank you. This is the kind of answer I was looking for. There are two things I’d like to give me feedback on:
1st: With 128 KB size blocks, there are roughly INFINITY possible blocks. I think the number 2^128000 is vastly superior to that of the number of atoms in the universe. This means that if anyone has a chunk needed to reassemble a copyrighted file, there is effectively almost 100% chance that he is the culprit. Therefore, the system offers no protection.
Assume that 100 million OFF users have 100GB each of hashes. that’s 10^18 (quintillion) bytes. Using some basic math, we find out that 2^59 is 5.8e18 which is a lower figure. This means that If the chunks used were only 59KB big, then a downloader would certainly get most of his chunks from people who did NOT have the copyright infringing file and who simply happened to randomly have one of the ingredients necessary to construct it. It’s like me saying I need block number 5412365125478563 which happens to be notepad. If I request 10 of those 16 digit numbers, i would be able to reconstruct Msn messenger. a thousand numbers for a DVD-quality movie and so on and so forth. In this case, the whole protocol would have to be outlawed because participation implies you are going to help infringe on copyright sometimes.
2nd: Since the SHA1 values are only for blocks of exactly 128000KB, wouldn’t it be extremely hard to the point of impossibility to create a collision and generate a garbage block of exactly 128000KB with the same SHA1 signature? This would get harder as the filesize got smaller I believe.