The Coldcard RNG failure was not due to a weakness in HW/SE RNGs.
The CC firmware’s multiple layers of complexity meant that the secure RNG was swapped for an insecure one. (They also never used SE RNG in Mk3)
I estimate that there is only <64 bits of entropy in these seeds
⚠️ I have strong reasons to believe Mk4/5 is also at risk, with those devices only having somewhat more entropy.
CHANGE YOUR SEEDS!!
npub122…cgrkj
2026-07-30 23:43:31 UTC
Author Public Key
npub12262qa4uhw7u8gdwlgmntqtv7aye8vdcmvszkqwgs0zchel6mz7s6cgrkjPublished at
2026-07-30 23:43:31 UTCEvent JSON
{
"id": "539e6dc97fd00dc1d36069e0696cdca61408901f466b95f84fd74cacebb3d6cd",
"pubkey": "52b4a076bcbbbdc3a1aefa3735816cf74993b1b8db202b01c883c58be7fad8bd",
"created_at": 1785455011,
"kind": 1,
"tags": [
[
"client",
"Damus"
]
],
"content": "The Coldcard RNG failure was not due to a weakness in HW/SE RNGs.\n\nThe CC firmware’s multiple layers of complexity meant that the secure RNG was swapped for an insecure one. (They also never used SE RNG in Mk3)\n\nI estimate that there is only \u003c64 bits of entropy in these seeds\n\n⚠️ I have strong reasons to believe Mk4/5 is also at risk, with those devices only having somewhat more entropy.\n\nCHANGE YOUR SEEDS!!",
"sig": "7933e65cf0fd7523f25873cf3c13d56f6fd36d7cf645a1e7fb51814f7fdd79c7266275921c1c918ab65fde4bc491881cffc42cd6b28b0a6a5f252846c9814cab"
}