Exchange Ranking
Top Exchanges
24h Volume Ranking
Popularity Ranking
Exchange BTC Balance
Proof of Reserves
Decentralized Exchanges
Funding Rate
Funding Heatmap
Liquidation Data
Max Pain
Long/Short Ratio
Whale L/S Ratio
Binance/Okex/Huobi L/S
Bitfinex Margin L/S
ETF Tracker
Solana ETF
XRP ETF
Hong Kong ETF
Bitcoin Treasuries
Crypto Reversal
Ethereum Reserves
HyperLiquid Wallet Analysis
Hyperliquid Whale Watch
Large Transactions
On-chain Movement
Bitcoin ROI
Stablecoin Market Cap
Options Analysis
News
Articles
Economic Calendar
Features
Wallet
Contract Calculator
Security
Collections
Watchlist
Following
BTC Entropy32 Plus: A new open source device that uses radioactive decay to generate Bitcoin mnemonics
A new open source device called Entropy32 Plus emerged. The device generates Bitcoin mnemonics by exploiting the unpredictability of radioactive decay. Its project aims to enhance cryptographic security by obtaining randomness from physical sources rather than relying on deterministic software random number generators.
Physical randomness based on radioactive decay
The operating principle of the Entropy32 Plus relies on a Geiger counter to detect decay events from radioactive sources or environmental background sources. Each detected event generates a unique electrical pulse that is transmitted through a 3.5mm audio interface for collection. These pulses provide entropy-the key measure of randomness needed for secure encryption key generation.
The device uses an LM393 comparator to convert analog signals to digital readings and sets the bias threshold at approximately 0.5V to ensure consistency of the output. The microcontroller measures the time interval between consecutive decay pulses and uses it as raw random data.
In order to improve the quality of entropy, the system uses the SHA-256 conditional processing mechanism to "white" the raw data, reducing statistical bias before mapping it to a 2048 word list that complies with the BIP39 standard. The resulting mnemonic words are fully suitable for offline protection of Bitcoin wallets, minimizing attack surfaces such as wireless connections or Internet exposure.
The accompanying documentation states that the device is "simple, auditable, and can be built by anyone with components that are readily available" and requires no external software support other than the included firmware."
Developers stated that the quality of the currently generated entropy has not yet been verified against the NIST SP800 - 90B standard. The standard provides guidance for evaluating physical and software-based random number generators.
Hardware Efficiency and Open Source Design
The core of the Entropy32 Plus is a custom PCB that uses the ATmega328P microcontroller, a compact and widely used chip. Firmware takes up 30,006 bytes of the chip's 30,720 bytes of flash memory, leaving little room for future updates. Memory limitations affect design choices, especially the inclusion of the BIP39 English vocabulary, which alone takes up 13,117 bytes, accounting for approximately 43% of the total storage capacity.
Due to these limitations, common display libraries such as Adafruit_GFX and Adafruit_SSD1306 cannot be integrated. As a result, firmware switched to memory-efficient U8x8 text mode to drive OLED screens. The device is also equipped with push-button driven menus, further supporting independent, secure operation.
Users interested in building the project themselves can find the complete Arduino code, SHA-256 implementation, KiCad circuit diagrams, manufacturing documents, and 3D printable shell designs in public repositories. The developers emphasized that Entropy32 Plus is an experimental build that has not been independently audited or externally verified, and users are advised to independently verify its entropy source.
