DRM News

According to Cryptopatents, MS has indeed patented a system that would allow users to make use of a peer to peer bit torrent network to download commercial software legally. That network would include several forms of encryption covering the entire network, as well as each individual data packet involved in the torrent download.

From the Cryptopatents article :

Microsoft’s permutation of this method is to individually encrypt each packet using several layers of encryption: public key cryptography, DES and RC4 for the algorithm’s different components.  The final encrypted packet is distributed to the network.

In an ideal setting, the scheme works like this: Microsoft sends you a master key that has been enciphered with your public key.  You decrypt the master key and the result is hashed using SHA.  The output is split in two, with the first part used as the root of the machine authentication code key (MAC, similar to a checksum), the second is the DES key. The DES key is used to decrypt the RC4 content key that, in turn, is used to decrypt the content payload.   The whole thing is XOR’d with the MAC and the output is reassembled for your viewing pleasure.

And yes, if that read like a giant paragraph of “Was that English?!”, welcome to the club. Essentially, how it seems the network encryption basically works is that you would receive an access key at the time of purchase. That key would ‘unlock’ torrent access, each piece of which is encrypted on its own. So even if one piece of the torrent were cracked, that still leaves dozens, maybe hundreds, of others to work on. It probably, like any other DRM system, isn’t uncrackable, but it would certainly take a substantial time investment on the part of hackers to do so. And since most software companies are using DRM to really try to avoid piracy over the initial launch period of a product, this would likely fit the bill.

On another note, it certainly is nice to see a commercial entity realizing that bit torrent doesn’t have to be left in the hands of the pirate community, and can actually be beneficial in a legal setting.