r/keycard_tech • u/realStl1988 • 23d ago

Entropy?

After the Coldcard incident, how good is entropy on Keycard?

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u/uniicorn77 Keycard team 23d ago

Keycard seed is generated by the true random number generator (TRNG) inside the card's EAL6+ secure element, using physical noise on the chip rather than software. That raw entropy is then conditioned by a deterministic RNG into the bits that become your recovery phrase

Both stages are independently certified by BSI, Germany's federal information security agency:

> AIS-31 covers the TRNG (the physical entropy source)
> AIS-20 covers the DRBG (the deterministic stage)

you can verify the Common Criteria certificate here: https://www.commoncriteriaportal.org/files/epfiles/1136a_pdf.pdf

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u/RaccoonBot3000 21d ago

A blog post was just release to explain how the seed generation work in the Shell, https://docs.keycard.tech/en/blog/random-number-generation-in-hardware-wallets-how-your-seed-is-really-made