ToBeDiscussed on Nostr: XOR does NOT add entropy. If all your shares come from the same broken RNG, or one ...

XOR does NOT add entropy. If all your shares come from the same broken RNG, or one attacker sees your other shares and crafts theirs adaptively, you're fucked.

Independence is everything. Use different hardware, different vendors, different codebases. I verified this on Coldcard Seed XOR myself:

Generated test seeds externally
Combined on device
Recomputed XOR bit-by-bit offline with a script
Cross-checked against the documented spec
It does exactly what it says:

The RNG bug in Coldcard firmware 2021–July 2026 proves the point. A single vendor fucked up entropy for years. If you'd XOR'd with an independent share, you'd still be safe.

Don't trust. Verify. Then XOR.

https://github.com/Coldcard/firmware/blob/master/docs/seed-xor.md

quoting
nevent1q…94wt

XOR is a one-time pad. If share A is truly random, then A+B is fully random even if B was generated by a backdoored PRNG, a state actor, or a deterministic joke.

The security comes from the math, not the manufacturer.

nevent1q…wqwm