Device for Generating Bitcoin Wallet Recovery Phrases Using Radioactive Decay Unveiled

A new open-source device called Entropy32 Plus has been unveiled, which generates Bitcoin (BTC) wallet recovery phrases using radioactive decay as a source of entropy. This device measures the time intervals between radioactive decay events with a Geiger counter and processes this data using SHA-256 to correspond to the BIP39 English word list. The device operates without a wireless connection and does not continuously store the generated recovery phrases. Users can generate and verify phrases using buttons and a screen. The hardware includes an ATmega328P microcontroller, a Geiger counter module, an LM393 comparator, and an OLED display. The developer has made the firmware, PCB circuit, and exterior design for 3D printing available, allowing users to prepare the components and build the device themselves while reviewing the code. However, the quality of the entropy has not been verified according to NIST SP 800-90B standards, and the developer advises against using it for wallets that hold large amounts of funds. Entropy32 Plus represents an attempt to secure initial entropy from physical phenomena. To prove its security, separate validation of the entropy quality, firmware, and hardware implementation is necessary.