The Russian Ministry of Interior is willing to pay 3.9 million roubles, or around $111,000, for a method to identify users on the Tor network.

The Tor software anonymizes Internet traffic by encrypting it and passing it through several random relays in order to prevent potential network eavesdroppers from identifying the traffic’s source and destination. The software was originally developed as a project of the U.S. Naval Research Laboratory, but is now being maintained by a nonprofit organization called The Tor Project.

The Tor network is popular with journalists, political activists and privacy-conscious users in general, but has also been used by pedophiles and other criminals to hide their tracks from law enforcement.

The Scientific Production Association for Special-Purpose Equipment and Communications of the Russian Interior Ministry is offering a contract for researching methods of obtaining technical information about users and user equipment on the Tor anonymous network, according to an entry on the Russian government’s procurement portal.

It’s not clear what Tor de-anonymization would be used for, but the fact that the tender comes from the Russian Ministry of Interior suggests that it could serve law enforcement investigations.

The FBI and police agencies in other countries have shut down illegal websites hosted on the Tor network in the past and even identified some of their owners and visitors. However, in most cases they exploited vulnerabilities in those sites or followed up on digital footprints left online by their administrators.

According to media reports last year based on secret documents leaked by former U.S. National Security Agency contractor Edward Snowden, the NSA and the U.K.’s Government Communications Headquarters had some success in de-anonymizing limited numbers of Tor users. However, they exploited vulnerabilities in the Firefox-based Tor Browser, not the Tor protocol itself, or attempted to use tracking cookies that persisted after Tor sessions were closed.

This doesn’t mean that there are no weaknesses in Tor that could allow third parties to unmask users. Two researchers from Carnegie Mellon University’s Computer Emergency Response Team (CERT) were planning to reveal a weakness next month at the Black Hat security conference that could allow an attacker with a $3,000 budget to de-anonymize hundreds of thousands of Tor clients.

The presentation was canceled at the university’s request because the information had not been approved for public release, but the weakness appears to be real. The Tor developers believe they’ve identified the issue and are working on a fix.

Given that reliable methods of identifying Tor users are extremely rare—as far as what is publicly known—and highly sought after, such a weakness would probably be worth much more than the $111,000 offered by the Russian Interior Ministry. A zero-day—previously unknown—remote code execution exploit for Apple’s iOS mobile OS can reportedly fetch up to $500,000 on the grey market and such exploits are probably more common.

“Anyone up for making a proposal for it, getting the money and then donating it back to Tor Project to fix the exact idea you raised with the money they just given you? That’d be a laugh!” one user wrote on the official Tor-Talk mailing list.