Ephemeral seed is temporary secret stored only in COLDCARD® volatile memory (RAM). It only survives single boot, meaning after Coldcard restart it is gone. Ephemeral seeds completely defeat the design of Coldcard's security model, based on secure elements.
Advanced/Tools > Ephemeral Seed
[<xfp>]is visible with fingerprint of ephemeral master secret
Advanced/Tools > Ephemeral Seed > Generate Seed
Advanced/Tools > Ephemeral Seed > Import Seed
Ability to generate and use Ephemeral seed is available on Coldcard when:
Import ephemeral seed via NFC. This is mostly for testing purposes as you need to have seed on mobile device which is very insecure.
If you intend to use the ephemeral seed feature frequently, you can define a "Trick PIN" which takes you to a "look blank" trick wallet (i.e. no seed set appears to be set). Then you may then safely unlock your Coldcard, without revealing the true PIN, and perform all your ephemeral seed work in that state.
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