unchained.comarticleπ‘οΈ SecurityUnchained explains how hardware wallets generate entropy for bitcoin keys, covering PRNG vs TRNG theory, physical TRNG mechanisms (ring oscillator jitter, diode avalanche noise, radio static reuse), and NIST SP 800-90B / BSI AIS-31 certification. It compares entropy sourcing and secure-element chip suppliers (STMicroelectronics, Microchip, Infineon, Espressif, Silicon Labs) across Trezor, Ledger, Coldcard, BitBox02, Foundation Passport, Blockstream Jade and Block Bitkey, and walks through the July 2026 Coldcard firmware bug that silently bypassed its hardware TRNG for five years, causing real bitcoin losses. It also covers manual dice/coin entropy generation for BIP39 seed phrases, the Dark Skippy nonce-leakage attack, and multisig as the primary mitigation against single-device key-generation failures.
BitcoinColdcardTrezor+3
Coldcard firmware vulnerability (2026)Dark SkippyMilk Sad+6
Hardware & RF, BlockchainΒ· Added 8 Oct 2026, published 7 Oct 2026