Tracking BitTorrent pirates isn’t all that hard since IP addresses are broadcasted publicly to anyone who’s interested.

With help from Internet providers, these addresses can then be linked to an account holder.

ISPs don’t hand over this data voluntarily; they typically require a subpoena or court order to take action. In the United States, these subpoenas are typically obtained by filing a copyright complaint in federal court against a “John Doe” who’s known only by an IP address.

Limited Retention

Internet providers typically store IP-address assignment details for a limited period that varies per company . For Comcast, this data retention period is 180-days.

The data retention policy has consequences for BitTorrent lawsuits. It means that rightsholders have to go to court within this window, if they want to unmask an alleged BitTorrent pirate.

This deadline is common knowledge and by now most rightsholders simply accept it for what it is. However, several recent movie piracy cases handled by attorney Kerry Culpepper show that there is another way to identify suspects, potentially for years after the infringing activity.

Borrowing Strike 3’s Records

The cases, filed on behalf of Capstone Studios, among others, targeted allegedly infringing IP-addresses that passed the 180-day deadline. However, since these same IP-addresses were previously targeted in lawsuits filed by adult producer Strike 3 Holdings, the film company saw an opening.

Instead of asking Comcast to dig up records that no longer exist, the movie companies asked the ISP to produce the subscriber information it had reportedly provided to Strike 3 for the same address.

Strike 3 is the most prolific rightsholder when it comes to filing BitTorrent piracy lawsuits, with thousands of new IP-addresses being targets every year.

These cases eventually landed on the desk of Magistrate Judge Cyrus Chung, who was skeptical about the tactic. In April, he denied the request, finding no reason to believe Comcast still held the requested information in its records.

“In short, the plaintiff provides no information that the third party has retained the information produced in the 2024 lawsuit, and the information it has provided affirmatively indicates that the third party does not retain such information,” Chung wrote in April.

Comcast Has the Requested Information

The movie companies didn’t give up easily and returned to court early June, with the missing piece. According to Culpepper’s declaration, Comcast had indicated that the records fell within its retention period for litigation documents.

Comcast’s retention limit for legal documents is longer than the 180 days for IP assignment logs, and the ISP purportedly said that it would produce the records if ordered. The movie company, meanwhile, agreed to pay the associated fees.

This new information was sufficient for Magistrate Judge Chung to grant the subpoena. In his order, he cites a 2009 federal appeals decision, Gotham Holdings v. Health Grades , that allows a party to subpoena documents that were produced in a separate lawsuit.

“Here, the plaintiff has shown that the third-party ISP possesses information relevant to its claim and that the limited discovery sought will not impose an undue burden or significant expense,” Judge Chung concluded, while granting the request.

This novel discovery technique is new for BitTorrent lawsuits. It means that, if a person is accused on one lawsuit, the chances that they are targeted in future cases increases, even outside the regular retention limit.

Are They the Same Person?

Taken together, the same IP address, the same client, a matching peer-ID fragment, do carry some circumstantial weight. The question is how much.

The ‘piggyback’ subpoenas were granted in at least four lawsuits, listed below, but there could be more. Whether this strategy will be used more regularly in the future has yet to be seen, but it raises a few questions.

The legal paperwork suggests that the defendants used the same IP-addresses, around the same time, as well as the same peer-ID. Therefore, plaintiffs conclude that they “are same person.”

However, it should be noted that in some cases, weeks have passed between the movie piracy and Strike 3 infringement, so in theory the IP-address could be assigned to a new person. The peer-ID argument tries to undercut that defense, but that also raises questions.

The legal paperwork references a peer-ID prefix, for example 2D5554333535572DC4B, which does indeed appear unique. However, most of this prefix (2D5554333535572D) identifies the torrent client ID in HEX, in this case it’s a version of uTorrent 3.5.5.

That would mean that only the three remaining characters of the prefix are unique. What complicates the matter further is that uTorrent typically generates a fresh peer ID per session , and a restart starts a new session, so the random portion of the ID changes.

Tit-for-Tat

All of this isn’t to say that the defendants aren’t the same people. The same IP address pointing to the same household, on the same client, is certainly possible and in many cases likely. However, proving it with certainty is another matter.

It’s also unknown whether any of these subscribers admitted wrongdoing in the related Strike 3 cases. Those suits are typically dismissed without context.

Whether Comcast will actually hand over the information has yet to be seen, but the plaintiffs arguments suggested that it has no objections before the subpoena was issued. If any subscribers are indeed targeted, they may also choose to push back.

For Capstone, the orders are welcome after the movie company lost a subscriber identification battle at the appeals court last year. There, the Ninth Circuit ruled that copyright holders can’t use a “DMCA subpoena shortcut” to identify internet subscribers suspected of copyright infringement.

As a result, rightsholders have to file slower more expensive federal lawsuits, including the ones at stake here. But with the new “piggyback” rulings, they are no longer tied to the 180-day retention windows.

—

Below are the four cases referenced in this article. The screenshots and quotes come from the first case, but the same language is often duplicated across cases.

– Capstone Studios Corp. v. Does 1-7, No. 1:25-cv-03564 — Silent Night. ( complaint , IP-addresses , motion for leave , and the granted motion )

– Capstone Studios Corp. v. Does 1-6, No. 1:25-cv-03561 — Breathe.

– Capstone Studios Corp. v. John Doe (73.95.253.148) – Silent Night

– Boy Kills World Rights, LLC v. John Doe (76.130.128.15) – Boy Kills World

From: TF , for the latest news on copyright battles, piracy and more.