Notes and the Book

The Book is an append-only Poseidon Merkle tree of note commitments, depth 26, with a ring of recent roots. One Book holds every mint, so the holders of every token stand in the same crowd.

A note

C = Poseidon(mint, amount, Poseidon(ownerKey, blinding))

Its opening (mint, amount, blinding) travels as a memo encrypted to the owner's viewing key.

A spent note

N = Poseidon(C, leafIndex, nullifierKey)

The nullifier account exists once the note is spent, so every note is spent once.

The invariant

For every mint, Vault[mint] holds at least the sum of that mint's unspent notes.

What the Book holds

Any token a wallet holds: every legacy SPL token, and Token-2022 tokens whose extensions are only their metadata and that have no freeze authority, pump.fun's included. The first deposit of a mint opens its Vault and FeeVault in the same transaction, and its name and symbol come from the mint's own metadata. From then on it is in the Book like any other: send it, swap it, state it, take delivery of it.

A mint the vault can't hold one for one is refused at deposit, with the reason: a transfer fee, a transfer hook, a non-transferable mint, confidential transfers, a permanent delegate, a pausable mint or accounts frozen by default.