Modifications to ZIP 207 3

The following paragraph is added to the section Motivation:

ZIP TBD 6 directs part of the block reward to a reserve, the distribution of which is to be determined via a future ZIP. ZIP 2001 7 modified this ZIP to augment the funding stream mechanism with a common mechanism to implement this proposal.

In the section Funding streams 4, instead of:

Each funding stream has an associated sequence of recipient addresses, each of which MUST be either a transparent P2SH address or a Sapling address.

it will be modified to read:

Each funding stream has an associated sequence of recipients, each of which MUST be either a transparent P2SH address, a Sapling address, or the identifier DEFERRED_POOL.

After the section Funding streams, a new section is added with the heading "Deferred Development Fund Chain Value Pool Balance" and the following contents:

Full node implementations MUST track an additional \(\mathsf{PoolValue}_{Deferred}\) chain value pool balance, in addition to the Sprout, Sapling, and Orchard chain value pool balances.

Define \(\mathsf{totalDeferredOutput}(\mathsf{height}) := \sum_{\mathsf{fs} \in \mathsf{DeferredFundingStreams}(\mathsf{height})} \mathsf{fs.Value}(\mathsf{height})\) where \(\mathsf{DeferredFundingStreams}(\mathsf{height})\) is the set of funding streams with a recipient of DEFERRED_POOL in the block at height \(\mathsf{height}\) .

The \(\mathsf{PoolValue}_{Deferred}\) chain value pool balance for a given block chain is the sum of the values of payments to DEFERRED_POOL for transactions in the block chain.

Equivalently, \(\mathsf{PoolValue}_{Deferred}\) for a block chain up to and including height \(\mathsf{height}\) is given by \(\sum_{\mathsf{h} = 0}^{\mathsf{height}} \mathsf{totalDeferredOutput}(\mathsf{h})\) .

Note: \(\mathsf{totalDeferredOutput}(\mathsf{h})\) is necessarily zero for heights \(\mathsf{h}\) prior to NU6 activation.

In the section Consensus rules 5, instead of:

• The coinbase transaction in each block MUST contain at least one output per active funding stream that pays the stream's value in the prescribed way to the stream's recipient address for the block's height.

it will be modified to read:

• In each block, for each active funding stream with a recipient other than DEFERRED_POOL at that block's height, the block's coinbase transaction MUST contain at least one output that pays the stream's value in the prescribed way to that recipient.

After the list of post-Canopy consensus rules, the following paragraph is added:

The effect of the definition of \(\mathsf{PoolValue}_{Deferred}\) above is that payments to the DEFERRED_POOL cause \(\mathsf{FundingStream[FUND].Value}(\mathsf{height})\) to be added to \(\mathsf{PoolValue}_{Deferred}\) for the block chain including that block.

Modifications to the protocol specification

In section 7.1.2 Transaction Consensus Rules 10, instead of:

The total value in zatoshi of transparent outputs from a coinbase transaction, minus \(\mathsf{v^{balanceSapling}}\) , minus \(\mathsf{v^{balanceOrchard}}\) , MUST NOT be greater than the value in zatoshi of the block subsidy plus the transaction fees paid by transactions in this block.

it will be modified to read:

For the block at height \(\mathsf{height}\) :

• define the "total output value" of its coinbase transaction to be the total value in zatoshi of its transparent outputs, minus \(\mathsf{v^{balanceSapling}}\) , minus \(\mathsf{v^{balanceOrchard}}\) , plus \(\mathsf{totalDeferredOutput}(\mathsf{height})\) ;
• define the "total input value" of its coinbase transaction to be the value in zatoshi of the block subsidy, plus the transaction fees paid by transactions in the block.

The total output value of a coinbase transaction MUST NOT be greater than its total input value.

where \(\mathsf{totalDeferredOutput}(\mathsf{height})\) is defined consistently with ZIP 207.

Note: this ZIP and ZIP 236 both make changes to the above rule. Their combined effect is that the last paragraph will be replaced by:

[Pre-NU6] The total output value of a coinbase transaction MUST NOT be greater than its total input value.

[NU6 onward] The total output value of a coinbase transaction MUST be equal to its total input value.

Section 7.10 Payment of Funding Streams 12 contains language and definitions copied from ZIP 207; it should be updated to reflect the changes made above.

In section 3.4 Transactions and Treestates 9, a definition of "total issued supply" will be added, such that the total issued supply as of a given height is given by the function:

The second paragraph of section 1.2 High-level Overview 8 should also be updated to take into account the deferred chain value pool. Since that section of the specification is entirely non-normative, we do not give the full wording change here.