Bring-your-own, the open question the migration plan left. Point this
wallet at a phrase you already hold — Minibits, Nutstash, cdk-cli — and
its coins become restorable here, which is the other half of "these
words are portable".
Replacing an established phrase is the one genuinely lossy thing this
module can do, so it is treated that way. The coins already held stay
spendable: they are proofs, not derivations, and nothing here touches
`ecash.json`. But they were minted under the *old* phrase, so a restore
will no longer find them. Hence an explicit confirm, a prompt to reveal
and write down the current phrase first, and — most importantly — the
replaced phrase is archived beside the wallet, never overwritten. It may
be the last copy of the words a balance was minted under, and quietly
destroying that is precisely what this module exists to prevent.
Re-importing the phrase already in use is a no-op rather than a
replacement, so it archives nothing.
Counters are deliberately left alone. They are per-keyset and
seed-relative, so under a new seed they merely start high, which costs
nothing because a restore scans from zero regardless. Resetting them
would be the dangerous choice on the day someone imports the phrase they
were already using.
`imported` is its own provenance rather than reusing `independent`: both
mean the node's recovery phrase does not cover the wallet, but only one
of them means the operator already knows where else the words live.
15 NUT-13 tests green, 1000 frontend tests green.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Running the route suite on this box surfaced that the backup was
unreachable here: `identity/master_seed.enc` is written during
onboarding, and any node onboarded before that step existed simply does
not have one. Reveal bailed with "this node has no encrypted seed
backup", and restore followed it down.
But the choice on such a node was never "derived phrase or independent
phrase" — it was "independent phrase or no backup at all", and a wallet
whose coins can be restored from words the operator holds beats one
whose coins die with a single file. So it now generates one, recorded as
`independent`, and every surface that shows it says plainly that
restoring the node will not bring the ecash back — only these words
will. `derivable_from_node_seed` lets the card say which kind you are
about to get *before* you write anything down.
Also: a mint that never implemented NUT-09 answered restore with a bare
404, which surfaced as "mint returned 404 with no further detail" —
true, and useless to someone trying to get their coins back. It now
names the limitation.
The route suite was reading `result.amount_sats` from mint-claim, which
answers with `minted_sats`. A working claim had been reporting as a
failure; that was one of the two reds carried over from yesterday.
The real gap, though, was that "recovered 0 sats" passes on a wallet
with nothing to find — exactly the shape of a backup that looks fine
until the day you need it. test-ecash-restore.sh does the test that
settles it: mint, **delete the wallet file**, restore, check the coins
came back. On this box: 87 sats before the wipe, 0 after, 61 recovered
from the phrase alone — every coin minted since the phrase existed, and
none of the 26 sats minted before it, which used random secrets and
never could come back. Testnet only, and it refuses to run otherwise.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Until now every Cashu proof this node held was backed by a secret drawn
from OsRng and written to exactly one file. Losing wallet/ecash.json
lost the coins outright — no phrase to write down, and nothing the mint
could do about it. Ecash is a bearer instrument, so "one file, no
backup" was the sharpest edge in the wallet.
NUT-13 derives each proof's secret and blinding factor from (seed,
keyset id, counter) instead. The wallet becomes a phrase, and the coins
can be re-derived and re-claimed — here or in any other NUT-13 wallet.
The phrase is its own 24 words, derived from the node master seed over a
fixed HKDF path. Both halves matter: it is still covered by the node's
recovery phrase, so there is nothing extra to write down; but it is
portable, so restoring ecash into Minibits or cdk-cli does not mean
handing over the key to the entire node.
It sits on disk unencrypted, deliberately. The master seed needs the
operator's password to open, which no background mint or swap can ask
for; and this file lives beside wallet/ecash.json, which already holds
spendable bearer secrets in plaintext. It regenerates exactly those
secrets, so it is the same sensitivity class as the file next to it.
0600, like identity/nostr_secret, which is derived and persisted the
same way.
Counters are reserved *before* the mint call and never rolled back. A
gap costs a restore scan a few extra probes; a reused counter costs a
coin, because two proofs with the same secret can only be spent once.
Restore is the half that cannot be done offline: a re-derived secret is
not money until the mint's signature over it exists. /v1/restore returns
those signatures; unblinding reconstitutes the proofs. It is additive
and idempotent — coins already held are skipped by secret, spent ones
are counted but not added — so it is safe to press on a working wallet,
which is when someone is most likely to reach for it.
Existing nodes activate on the first visit to Settings → Ecash backup
phrase: that password prompt is the only moment the master seed can
legitimately be opened. New nodes get it at onboarding. Until then the
behaviour is exactly as before — valid proofs, no backup — and the card
says so rather than implying a backup already exists.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
archipelago