What happened
On 17 August 2026 a Nostr application was merged into
BIP-85, the
specification for deriving many secrets from one seed, in Bitcoin's proposal repository.
Pull request #2126 assigns Nostr the
application number 128002' and the derivation path
m/83696968'/128002'/{identity}'/{account_index}'.
What it changes
BIP-85 exists because backups multiply. Its stated problem is that keeping separate seed backups across incompatible wallet standards is awkward to secure and awkward to store. Its answer is to derive child entropy from one master keychain at a fixed path, so a secret can be regenerated on demand from a seed you already have rather than written down again.
The Nostr application makes a Nostr secret key one of those regenerable secrets. The specification is short: "Take the first 32 bytes (the 256 most significant bits) as the secp256k1 secret key... Encode the secret key in Bech32 with the nsec human-readable part as specified by NIP-19." The same words that back up your coins now reproduce the key that signs your posts.
The part worth reading twice is that the path has two levels rather than one. Each
{identity} is, in the specification's words, "an independent, unlinkable Nostr key
namespace"; each {account_index} is a distinct key inside one of them. Rotating a key and
starting a separate persona are therefore different movements, along different axes, rather
than the same undifferentiated act of generating another key. Index 0' is reserved at
both levels for key management - "proof-of-linkage between an identity's keys, key
rotation, and revocation", so usable keys begin at 1'.
If deterministic derivation sounds familiar, it is the same trade this site has already examined for deterministically derived passwords: fewer things to store, and one thing whose loss is now total.
What it does not change
The derived key is still a hot key. A Nostr secret key lives in a browser extension or an app because it has to sign constantly, and deriving it from a seed phrase does not move it somewhere safer - see the ways people log in to Nostr for what that exposure actually looks like.
It also widens what one backup is worth. Derivation runs one way, so a leaked Nostr key does not expose the master seed. The reverse is the point: the seed now stands behind an identity as well as savings, and those two things face very different daily risks.
"Unlinkable" is a statement about the keys, not about you. Two identities derived from one seed cannot be tied together by anyone examining the keys. Anything either of them posts is a separate matter entirely.
And a merged specification is not shipped software. Nothing in any wallet or client changed on 17 August.
Context
Whether Nostr belongs in the Bitcoin proposal repository at all was raised in the pull request discussion, and the answer that carried it came from wallet developers rather than from Nostr ones: Nostr identities are already being used as payment contacts, and there is work on passing PSBTs and coordinating multisig over Nostr. On that reading this is less an identity feature than plumbing for wallets that have started to need a name to send things to.