Microsoft CEO Satya Nadella closed out Sibos 2017 with what sounded an awful lot like a challenge.

At day three of the annual financial conference, hosted by interbank messaging service Swift, Nadella provided a footnote on what was otherwise an event focused largely on collaboration between fintech startups, but which left blockchain out of the spotlight during several key addresses.

That, however, wasn’t the case as the conference closed.

Following a question posed onstage by Swift CEO Gottfried Leibbrandt about whether blockchain was all it’s been cracked up to be, Nadella responded definitively.

He told the audience:

“There’s real tangible progress that can be made. But, I think it’s in your hands that it has to be converted into things that are very useful.”

Nadella’s apparent challenge to Swift is especially nuanced as the platform that connects 11,000 of the world’s banks has been conducting its own successful experiments with the technology that some say could render its service obsolete.

Elsewhere, Nadella’s comments focused on Microsoft’s blockchain announcements at Sibos, and the company’s support of blockchain through its Azure cloud platform.

On a more personal note, though, he went so far as to reflect on his own time as a programmer at Microsoft, framing blockchain as the fulfillment of a long-held personal aspiration.

“Ever since at least I’ve been in this industry, we’ve always looked for a distributed database with a trust harness that allows multiple organizations to collaborate, and that performs,” he said, continuing:

“Clearly, the blockchain and the distributed ledger that exists underneath it, I think is a very novel implementation, which I believe can have massive implications.”

Satya Nadella and Gottfried Leibbrandt image courtesy of Swift