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Ephemeral Seeds Usage Trick PIN Notes Purpose
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Ephemeral Seeds

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 defeats the design of Coldcard's security model, based on secure elements.

Make sure you know what you're doing!

Usage

  • go to Advanced/Tools -> Ephemeral Seed
  • if ephemeral seed is already in use, the menu option CLEAR [<xfp>] is visible with fingerprint of ephemeral master secret
  • an ephemeral seed can be Imported or Generated at random
  • Generate:
    • Advanced/Tools -> Ephemeral Seed -> Generate
    • same options as generating new seeds, dice rolls included
  • Import:
    • Advanced/Tools -> Ephemeral Seed -> Import
    • same options as importing seeds
  • an ephemeral seed can also be a BIP-85 derived value

Trick PIN Notes

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 (ie. 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.

Purpose

This feature is intended for those one-off signings, like recovering a lost seed from some other system or importing some seed as an balance check. We do not recommend handing unencrypted seed material on a regular basis!