On Thursday, Anonymous posted a new operation announcement video to YouTube, announcing the initiation of #OpBrussels. Among the non-hierarchical hacker organization’s claims was the following: “We severely punished ISIS on the darknet, hacked their electronic portfolio, and stole money from the terrorists.”

True to Anonymous form, the video features a masked operative vaguely threatening an amorphous organization, ISIS, on behalf of his own amorphous organization. This operative, cloaked in cascading, green, Matrix-esque symbols, explains that Anonymous has already shut down “thousands of Twitter accounts directly linked to ISIS.” He goes on to say that, together, Anonymous has “laid siege to [ISIS’s] propaganda websites, tested them with our cyber attacks.”

The speech continues, taking on a different tone, and urging the public to support its efforts:

“Everyone can contribute to our efforts and we invite you to fight with us, you can find information about the operation in the description of this video. The Islamic state can not recruit Muslims in Europe if they are accepted and included in the society. So we want all of you to stand together against discrimination.”

In another video, that is verbatim but, for some extra elaboration, a Guy Fawkes mask–adorned individual says that this approach is more useful than hacking Twitter accounts and temporarily shutting down propaganda websites.

Perhaps the most intriguing, impactful claims in the video, though, are that Anonymous managed to infiltrate ISIS’s electronic portfolios. The claims are vague — “stole money from the terrorists” — and lack concrete, supporting evidence. No less, many believe that ISIS funds a majority of its operations with bitcoin. And, contrary to what you might assume, it is actually possible to steal bitcoin.

In fact, bitcoin thefts occur with relative frequency. A list of “major bitcoin heists, thefts, hacks, scams, and losses” shows that the three most severe heists or losses were equivalent to $700 million, $26 million, and $4 million.

Since bitcoin is a cryptocurrency, and does not exactly exist in physical form, it’s somewhat easy to steal, given one specific tool: the cryptographic key that unlocks the addresses within which the bitcoin exist must be somewhere accessible. If you own bitcoin, you’ve either a) wisely written this key down in physical form — on a piece of paper, say — and hidden it away in a dark recess of your closet or a time capsule six feet under or b) put it in a file labeled “HERE ARE MY BITCOIN KEYS.” If ISIS does something along the lines of the latter, then Anonymous could presumably have hacked into their files and stolen funds.