Zach Herbert, co-founder and CEO of Foundation, said in an Oct. 22 interview on Unchained Premium that the Ethereum Foundation is launching an app called the Universal Ethereum Signer on KeyOS, the operating system that runs on Foundation’s Passport Prime device. The EF is doing it in partnership with developer Nicolas Bacca, a Ledger co-founder who wrote the app, Herbert said.

Herbert called it the first time the EF has collaborated on a “signing app to run on hardware wallet-like devices.”

Neither the EF nor Foundation had posted about the app as of Nov. 4. Its code sits in a public GitHub repository under the Ethereum organization, which describes the project as “a reference implementation for Ethereum hardware signers.” The repository lists no releases, says a download channel for the KeyOS version is still being worked out, and warns that the code has not been audited. It says later versions may add Clear Signing, the standard the EF introduced in May.

Herbert also said in the interview that Bacca got developer units after meeting Foundation’s team at what he believed was one of the conferences in Europe, and “he started building this app on his own.” Foundation never held a formal sit-down with Bacca to spec out the app with the EF, Herbert said, adding that he didn’t think Bacca talked to the company about it until he had built something.

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How Apps Reach the Device

For now, users install the signer by sideloading it from a computer or flash drive and choosing to trust the developer’s certificate, Herbert said. KeyOS keeps each app in its own sandbox and hands it a hardened key derived from the user’s master key instead of the master seed, so a malicious app “cannot break out of its sandbox,” he said.

Foundation plans an app catalog with a review process for apps. Organizations that are “trusted by the community” will also be able to ship updates and emergency patches straight to users, much as F-Droid works on GrapheneOS, he said, naming the EF as an example. On Oct. 22 he said the catalog would arrive “over the next month or two.” Foundation had not announced a launch date as of Nov. 4.

Herbert estimated that Foundation has handed out “probably over 200, maybe over 250” of the 1,000 devices it set aside for developers.

After the Interview

Days after the taping, Foundation disclosed that attackers had reached some of its backend systems and sent phishing emails to customers. “Funds stored on Passport are safe and Passport hardware is not compromised,” the company said on X. Herbert said Foundation would share a formal report. The company has since posted several incident updates on its community forum and says the full report will follow when its investigation is complete.

Watch the full conversation on Unchained Premium: Premium members get the complete interview with Foundation’s Zach Herbert on why the Ethereum Foundation is launching a signing app on Passport Prime. Watch it here.