You do not depend on us
A backup tool that only works while its maker is around is not a backup tool. So there are two answers to “what if ShamirVault disappears”, and both can be checked today.
One: split with SLIP-39 and it is not our problem
ShamirVault can split using SLIP-0039, the standard Trezor and other wallets implement. Parts in that format are twenty or thirty-three words that any compatible implementation reads. Our implementation is validated against the 45 official test vectors published by SatoshiLabs and Trezor.
If you choose that format, this page is irrelevant to you: the standard outlives us.
Two: the own format, documented and with a reference script
The format ShamirVault uses for free text is not a standard, so it comes with two things instead:
- A specification describing every byte: the header of a part, the checksum, the arithmetic over GF(256), the digest of the secret, and the containers for passphrase-protected secrets and files.
- A reference script in Python that recovers a secret using only the standard library. No install, no dependencies, about three hundred lines you can read in one sitting.
The script checks itself against vectors generated by the app: run it with --autoprueba and it tells you whether it still agrees with the format.
Download them and keep them with your parts
The sensible thing is to save both next to your parts, or print the specification and put it in the same envelope. They are worth nothing on their own and cost nothing to keep.
Specification: formato-partes.md · Reference script: recuperar.py
What the own format does not do
- It is not interoperable: no other tool reads it. If that matters to you, split with SLIP-39.
- It does not hide the size of the secret.
- It does not protect against someone who already holds enough parts. That is not a flaw, it is the definition of the scheme.