Accounts and notes

Miden state is held in accounts and moved by notes. Every port0 operation is a note that targets an account.

Accounts

Three account kinds appear in the system:

A public account stores its full state on chain. A private account stores only a commitment on chain and keeps the state with its holder. A pool is a public account: its reserves, LP supply, fee rates, and oracle readings are readable by anyone.

An account id is two field elements, prefix and suffix, and renders as 0x-prefixed hex or as a bech32 address.

Network accounts

A network account installs the network-account auth component. The component carries a note-script allowlist, the fee policy, and the nonce handling, and the node’s transaction builder reads the allowlist to consume notes on the account’s behalf. No signing key is involved. Removing the component turns the account into an ordinary account the node does not service.

Every transaction executed by a network account must have an effect: an input note, an output note, or an account state change. An empty scriptless transaction is rejected. A new network account is therefore committed by consuming a funding note as its first transaction, which also pays the first transaction fee from the received funds.

Both the pool and the registry are network accounts.

Notes

A note carries a script, storage, and assets. The script runs in note context and calls an account procedure through the component interface. Note scripts may not create output notes or move assets directly; account procedures may.

A port0 feature note is a public network note: it carries a NetworkAccountTarget attachment bound to the target account, so the node’s transaction builder can route it. Each feature note travels with a separate FEE_SPONSORSHIP note that pays the target’s configured note consumption fee.

Note fees

Notes carry a fee. A fee asset is required to consume a note, and the executing account pays it from its own vault. A pool’s fee faucet must equal the chain’s fee faucet, or the node never consumes the pool’s notes. On the Miden testnet the chain fee asset is USDCX. It comes from the network faucet; it is not minted by this project.

The registry prices two note kinds in its network auth: the register note at the configured register fee, and the registry-collect note at zero, because collection is permissionless and unsponsored. The registry pays the registry-collect transaction fee from its own vault.

Output notes and foreign calls

An account procedure can create output notes, which is how a pool returns LP tokens, refunds, swap output, and collected fees. Output notes use the P2ID script by default, with the recipient and the pool’s stored P2ID root.

A pool reads its protocol fee destination from the registry by foreign procedure invocation. The registry reads a pool’s code commitment and identity the same way at registration. The registry holds the protocol fee destination once for every pool, and it is read only on the collect path.