A note on a payment from the Cardano account: CIP-20’s transaction
message, metadata label 674 holding { "msg": [lines] }, which wallets
and explorers show with the transaction. Anyone can read it, for good.
The outputs behind the Seedelf contracts’ reference UTxOs (output #1 of
the transactions in crate::constants), byte for byte as they sit on
chain, so a transaction that reads them can be evaluated in the wallet
without asking anyone for them. They never change: the scripts are
immutable and the UTxOs are held by an always-false script.
A zero withdrawal from a script’s reward account, with its redeemer: the
“withdraw-zero” pattern, where a script registered as a stake credential
runs once per transaction to check the whole of it. Lovejoin’s mix_logic
works this way: every mix and every withdraw of a box carries one.