After the Coldcard entropy story, a lot of you asked the obvious follow-up: how does Jade handle this?
So we went and read
@Blockstream ‘s own breakdown, plus the source code. Here's the short version.
The risk is the same for every hardware wallet: a private key is only as safe as the randomness used to create it. If that randomness is weak, an attacker doesn't need to steal your device… they can just guess.
Jade's answer is to never rely on a single source.
While the device is running, it continuously pulls entropy from several independent places at once:
→ User interaction — button presses and the wheel
→ CPU counters
→ Battery state
→ Ambient temperature
→ Several camera frames captured during boot: even pointed at a blank desk, the sensor noise is usable randomness
→ A built-in hardware random number generator
→ Entropy contributed by the companion app on your phone
One detail worth knowing: Jade's hardware RNG partly draws from the device's radio. Run the "No-Radio" firmware and you lose that input… so Blockstream compensates by sampling raw radio noise once at boot, before the radio is disabled, and folding it into the mix anyway.
All of this feeds into an accumulator modeled on the same approach Bitcoin Core uses: a 32-byte internal state, updated by hashing itself together with fresh entropy through SHA-512. The hash output is split… half becomes the new internal state, half is handed off to generate your recovery phrase. That hashing runs constantly, including every time you touch a button.
Two things stand out compared to a single-source design:
1. There's no one point of failure. If one sensor is noisy, biased, or misconfigured, the others still contribute.
2. New entropy is always added on top of the old, never used to replace it… so state never gets "reset" to something weaker.
It's not a guarantee against every possible flaw: no design is. But it's a meaningfully different risk model than depending on one RNG path end-to-end, which is exactly the assumption that broke down elsewhere this year.
— BitCorner
#Bitcoin #Cybersecurity #HardwareWallet #InfoSec #OpenSource
