Ethereum Foundation launches Universal Ethereum Signer app on Passport Prime
The Ethereum Foundation has launched the Universal Ethereum Signer app on Foundation's Passport Prime device, developed by Ledger co-founder Nicolas Bacca.
The app runs on KeyOS, the operating system behind Foundation's Passport Prime device. This marks the first time Passport Prime can act as a dedicated signer for Ethereum transactions through a third-party application. The Universal Ethereum Signer allows users to review and sign Ethereum transactions on separate, air-gapped hardware rather than trusting a phone or laptop with their keys.
Development and Beta Status
Bacca, now CEO of ZKnox, built the app with funding from an Ethereum Foundation grant to ZKnox. The app is currently in beta and requires users to sideload it manually onto Passport Prime. Sideloading means installing software directly rather than downloading it from an official store.
The app was written by Nicolas Bacca, a Ledger co-founder, and the Ethereum Foundation is working with him on the launch
Future Plans and Security
Herbert mentioned that a future app catalog will allow trusted groups to push updates directly to users, expected to launch in winter 2026. This model resembles F-Droid on GrapheneOS, where independent developers can ship software without waiting on a central gatekeeper.
Passport Prime, which retails for $349, features a 3.5-inch touchscreen and 50 GB of encrypted storage. It combines Bitcoin hardware wallet functions with FIDO security keys, two-factor authentication, and encrypted file storage. The device runs KeyOS, an open-source microkernel written in Rust designed to isolate apps from one another.
In October 2026, Foundation dealt with a phishing campaign targeting more than 23,000 customer emails, though devices and private keys remained uncompromised. The addition of Ethereum support expands transaction types and approval screens users need to understand before signing.
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