Bitcoin Magazine has published a guest essay by Obi Nwosu, co-founder of Fedi and Fedimint, arguing that Bitcoin custody is being framed with the wrong question. Instead of treating every design as either "trusted" or "trustless," he wrote that the real test is this: how many independent things have to go wrong before users lose their money?
The article notes that the views are Nwosu’s alone and do not necessarily reflect those of BTC Inc. or Bitcoin Magazine.
From trust language to failure domains
Nwosu said he had made the same point a few weeks earlier, when he argued that the ecosystem kept asking the wrong question. He pointed to discussions around Liquid and, weeks before that, Coldcard. In his telling, Matt Corallo captured the problem in a short line: run the same software, suffer the same bugs.
That criticism, he wrote, also applied to Fedimint. He said he was the first to acknowledge it. Fedimint was built to remove single individuals and single institutions as points of failure, but underneath those human federations there was still only one implementation of the protocol. That left a software monoculture in place, which he described as not secure enough.
Berlin demo put one federation on three implementations
According to the essay, Fedimint developers have already started to answer that problem. At Ecash Hackday in Berlin, the Fedimint team got a single federation running across three independent implementations, with one of them built by Cashu’s thesimplekid.
Nwosu cited a Sept. 30, 2026 post from elsirion that read: "Had a great time at Ecash Hackday in Berlin, got a Fedimint running with 3 different implementations by @thesimplekid, me and the Fedimint team! Already got 3 Fedimint implementations now, who will build the 4th one?"
His point was straightforward. Three separate codebases were able to hold funds together inside one federation. He presented that as an early answer to the monoculture issue he had raised weeks earlier, and said the call for a fourth implementation reflected exactly the kind of mindset he wanted to see.
Calle introduced Federated Cashu at bitcoin++
Nwosu also highlighted a second line of work. He wrote that Calle unveiled Federated Cashu at bitcoin++, describing it as a design where no single operator stands alone behind a user’s funds.
The piece quotes a post from Matthew Vuk dated Oct. 1, 2026, summarizing Calle’s presentation at @btcplusplus. The quoted remarks were: "You don’t need to trust the operator with your privacy, but you do need to trust the operator with your security" and "Any combination of 4/5 continues the federation." The post also said a new Blind BLS signature scheme is involved.
Nwosu framed the development this way: two teams, two approaches, one shared goal. In his view, both efforts pushed ecosystem resilience forward within the span of a few weeks.
Why multiple layers of independence matter
He argued that fault tolerance does not come from trustworthiness alone, no matter how strong audits, formal verification, or security culture may be. What matters, he wrote, is the presence of independent failure domains, so that no single bug, no single vendor, and no single jurisdiction can take everything down at once.
Nwosu then drew a distinction between the protocol and the product built on top of it. Fedimint, he wrote, is the open-source protocol. Fedi is what his team builds on top of that protocol. Once the protocol has a second and third implementation, every federation becomes more resilient, while federation members do not need to change how they use their wallet. Guardians can run different software while still serving the same users.
The five layers he said the ecosystem should demand
Nwosu said he had previously laid out five layers where independence needs to hold, and repeated them in the article:
- Multiple implementations of every protocol that holds funds.
- Multiple wallet implementations.
- Keys generated on hardware from different vendors.
- Multiple independent, trustworthy people behind every system that holds money, with their privacy protected.
- Distribution across geographies and jurisdictions, because the rules in a jurisdiction can change overnight.
He said the developers who worked on the Berlin effort moved those five layers closer to reality. He thanked those continuing to build and share their proof-of-work, but added that the work is not finished.
His closing argument was that the ecosystem needs to demand independence at every layer: software, hardware, humans, and jurisdictions, all the way down. That, he wrote, is how Bitcoin can maintain user confidence as the ecosystem enters what he called a new age of AI-assisted threats.
The article first appeared in Bitcoin Magazine and was written by Obi Nwosu.