[ZIP 272]: Consensus Accounts

[nuttycom]

The Zcash development fund lockbox currently has the characteristics of a
transparent, account-based system. Spending from the lockbox requires the
introduction of a new transaction bundle that treats the lockbox as a source of
transaction inputs, controlled by a key that may be rotated using the mechanism
specified in ZIP 270 [^zip-0270]. Instead of creating a mechanism that is
specific to the development fund lockbox, creating a general mechanism provides
several benefits to consistency and usability.

[linear]

COR-628

[nuttycom]

An idea that came to me this morning in discussion with Zooko is that consensus accounts could serve a role in an "automatic unstaking" mechanism. The flow would roughly be:

• When staking, a user specifies the consensus account ID that will control the funds in any eventual unstaking action. They provide a signature proving control of that consensus account.
• When unstaking, the user signs the unstaking action with the consensus account key, and provides a shielded address that the funds will be unstaked to when the withdrawal period is up.
• The unstaking action immediately transfers the un-staked funds to the consensus account.
• When the withdrawal period is up, the consensus protocol moves the unstaked funds into a UTXO controlled by the shielded address as part of the coinbase transaction.

[daira]

Assigned ZIP number 272 with @str4d @nuttycom @aphelionz.