In its long fight against Internet piracy, the Recording Industry Association of America is gunning for the technology that enables it: BitTorrent.

Brad Buckles, RIAA's VP for anti-piracy, has told the CEO of BitTorrent he's "very concerned about the overwhelming use of BitTorrent Inc. developed clients" in pirating his members' works. BitTorrent software, including the popular uTorrent client, "facilitated approximately 75% of the over 1.6 million torrent based infringement of our members' works last year in the US," Buckles wrote in a letter dated July 30.

"Like it or not, BitTorrenting products are the premier products used for peer-to-peer infringement today," RIAA deputy general counsel Victoria Sheckler told Mashable, which published the letter yesterday. "In private discussions that various people have had with BitTorrent over the last few years, they've refused to address the elephant in the room, which is the piracy over the BitTorrent protocol."

Contacted by Ars today, the RIAA declined to comment beyond Sheckler's previous statements.

Buckles' letter states that RIAA took a random sample of 500 audio torrents selected from BitTorrent's "distributed hash table," and found that 82.4% of them were commercially available "and therefore highly likely to be protected by copyright." Buckles adds:

Matt Mason, the Chief Content Officer at BitTorrent has stated that "The piracy happens outside the BitTorrent ecosystem." But, as the above data clearly shows, this argument is disingenuous when BitTorrent Inc. itself is the source of the software that is used so overwhelmingly for infringement. ... To quote Mr. Mason yet again, "We don't endorse piracy." If that is indeed your business philosophy, then we believe it is only right and proper for BitTorrent Inc. to take steps to reduce their facilitation of infringement. We look forward to hearing from you on next steps.

The letter suggests that RIAA could help "establish a process to share... hashes with BitTorrent, Inc. on a regular basis" so the company could use that data to "deter further infringement." Buckles also states that RIAA knows several companies that "offer services to help identify infringing torrent sites and files."

The letter doesn't explicitly suggest filtering content, but sharing hashes to "deter infringement" suggests that is what the RIAA has in mind. uTorrent is a popular piece of software, but there are dozens of programs for sharing torrent files.

The new RIAA request comes as BitTorrent notes the 10th anniversary of its "distributed hash table," a milestone noted in the letter. Last week, news reports noted that the RIAA also sent a letter to CBS complaining about CNET's software download site, which makes software that enables "ripping the audio... from what might otherwise be a legitimate stream."

Correction: The original version of this article stated BitTorrent experienced its 10th anniversary this year. BitTorrent was first released in 2001. The company's "distributed hash table" or DHT is 10 years old.

Update: BitTorrent spokesperson Christian Averill responded to Ars on Wednesday, saying: "They are barking up the wrong tree, as it seems they were with their approach to CBS last week. There is a distinction between the BitTorrent protocol and piracy. We do not host, promote, or facilitate copyright infringing content and the protocol, which is in the public domain, is a legal technology."