A Geiger Counter Writes Your Seed Phrase
An open-source Bitcoin hardware project has found one of the strangest possible sources of randomness for wallet creation: radioactive decay. The device, called Entropy32 Plus and nicknamed “The Universe Bifurcator,” converts the unpredictable timing of atomic decay events into standard 12-word and 24-word BIP39 recovery phrases — entirely offline. Developer Alexander Higgins published the project’s repository on GitHub in September 2026, describing it as an experimental, educational effort and explicitly warning users not to trust it with substantial funds before an independent review.
The concept taps a physical fact that cryptographers have long appreciated: while the decay of any single radioactive atom cannot be predicted, its arrival can be measured. Entropy32 Plus takes pulses from a Geiger counter and measures the time between detected events, turning comparisons between consecutive intervals into the raw bits that ultimately become a wallet’s master seed — the single secret from which every private key and address in a Bitcoin wallet is derived.
How Decay Becomes a 12-Word Phrase
According to the project documentation reported by crypto.news on Sept. 13, the current design accepts pulses through a 3.5-millimeter connection from a GQ Electronics GMC-320S Geiger counter, which can detect emissions from either a radioactive source or ordinary background radiation. An LM393 comparator converts the counter’s analog signal into a digital input, and a custom circuit board passes it to an ATmega328P microcontroller — the same humble chip family that powers Arduino boards.
The firmware records each accepted event with a microsecond timer and compares the latest interval with the one before it, producing a one when the new interval is longer and a zero when it is shorter. Equal intervals are discarded, and measurements below 200 microseconds are rejected as possible glitches. The process continues until the device has collected a 512-bit input pool — twice as many bits as the maximum 256-bit BIP39 input the device will produce.
That pool is then processed through the project’s bundled SHA-256 implementation. Hashing is intended to reduce visible patterns linked to detector dead time, count-rate changes, or correlations between measurements. For a 12-word phrase, the firmware uses the first 16 bytes of the resulting hash and calculates a four-bit checksum, dividing the combined 132 bits into twelve 11-bit groups, each of which selects one word from BIP39’s standardized list of 2,048 words. The 24-word setting uses 256 bits plus an eight-bit checksum.
Deliberately Airgapped, Deliberately Temporary
The design choices around storage are the most wallet-conscious part of the project. The device operates without Wi-Fi, Bluetooth, or any persistent seed storage. Generated words are held temporarily in RAM, and a manual wipe command clears them afterward. The firmware also runs a startup self-test, hashing the string “abc” and comparing the result with a known value; the device refuses to collect entropy if the answer is incorrect.
Higgins has published the full stack for inspection — firmware, circuit-board designs, fabrication data, printable enclosures, and the BIP39 wordlist — in keeping with the hardware-wallet community’s insistence that security through obscurity is no security at all.
The Honest Fine Print
What distinguishes this project from marketing-driven hardware wallets is how blunt its developer is about the limits. The repository states that entropy quality remains unvalidated under NIST SP 800-90B testing and has not undergone independent review. Passing the SHA-256 self-test confirms only that the implementation returns the expected result for one test vector — it does not test the Geiger counter, assess whether pulses are truly independent, or measure the minimum entropy entering the hash.
The distinction matters more than it might first appear. Hash conditioning can spread available entropy across an output, but it cannot prove how much unpredictability was present in the original data. A seed phrase is not a collection of independently random words; weakness in the original entropy can affect every address generated from it. For a wallet holding Bitcoin — trading near 77,000 USD in the current market — that chain of dependence is only as strong as its weakest link.
Why Physical Entropy Keeps Attracting Builders
Entropy32 Plus joins a long tradition of do-it-yourself randomness experiments, from dice-rolled seed phrases to camera-sensor noise collectors. The appeal is understandable: software random number generators have suffered catastrophic failures historically, and a physical process grounded in quantum mechanics feels reassuringly indifferent to hackers.
The project’s real value may be educational rather than practical. It forces users to confront what a recovery phrase actually is — an encoding of entropy that anyone holding it, in the right order, can use to recreate a wallet’s keys. Until an independent security assessment validates the decay-timing approach, the developer’s own advice stands: treat it as a fascinating experiment, not a vault.
an atmega328p and a GMC-320S rolling your seed is peak bitcoin energy. my question is whether the sha256 pass really kills the detector dead time bias or just hides it
higgins claims the whitening pass handles it in the docs, but until someone runs dieharder on the raw bitstream its faith not entropy
using background radiation means no isotope shipping or licensing hassle. clever compliance dodge lol
hashing spreads the entropy around but it cant create any. until someone independent audits that timing circuit ill stick with dice and a steel plate
^ dice gang. 99 rolls, a steel plate, zero firmware updates to trust
The LM393 comparator detail is fine, but I would want independent entropy testing on the full bitstream before trusting it. NIST test suites exist for exactly this reason.
timing gaps between decay events, that is proper physics randomness. still agree, run the test suites first
Running the NIST suite on a few million captured bits is exactly what an independent review should publish. Until that exists, dice win.
higgins naming it the universe bifurcator is a harder name than any hardware wallet marketing team ever shipped
a 30 dollar geiger counter outperforming hardware wallet rngs is the funniest outcome of the year. dice still undefeated tho