An open-source project called Entropy32 Plus has introduced an offline Bitcoin seed generator that uses radioactive decay timing as a physical source of randomness. Published by developer Alexander Higgins in September 2026, the repository includes firmware, circuit-board designs, fabrication files, enclosures and the BIP39 English wordlist.
The device, known as The Universe Bifurcator, takes pulses from a Geiger counter and measures the time between detected events. It compares consecutive intervals, converts those comparisons into bits, collects a 512-bit input pool, and processes it with a local SHA-256 implementation. The firmware then maps the conditioned data to standard 12-word or 24-word BIP39 recovery phrases, using either 128 bits or 256 bits depending on the selected phrase length. It operates without Wi-Fi, Bluetooth or persistent seed storage, displaying words on a 0.91-inch OLED screen and keeping them only temporarily in RAM.
The project emphasizes physical isolation as a security benefit, but it also includes clear limitations. The entropy source has not been tested under NIST SP 800-90B, and no independent audit or public raw-event dataset was included as of Sept. 13. The developer describes the device as experimental and educational, warning users not to trust it with substantial funds before an independent review. The firmware passes a SHA-256 startup self-test, but this does not validate the Geiger counter, assess pulse independence, or measure minimum entropy.
Because BIP39 seed phrases can derive many Bitcoin private keys from one master seed, weak original entropy can affect every address generated from it. The project documentation recommends mixing the Geiger-derived data with another independently validated source before creating a wallet for valuable funds. Entropy32 Plus remains under active development, with no tagged production release or published timetable for completing an independent security assessment.
