Transaction Format

The following field is added to the v6 transaction format 8.

Consensus Rules

The following changes are to be made to the Zcash Protocol Specification 2.

In § 3.4 ‘Transactions and Treestates’ 3 (last modified by ZIP 236 9), add the following consensus rule and note:

• [NU7 onward] For v6 and later transactions, the remaining value in the transparent transaction value pool, in zatoshis, MUST be equal to the value of the transaction’s fee field.

Non-normative note: The effect of these rules is that the fee field of v6 and later coinbase transactions will always be zero.

In § 7.1 ‘Transaction Encoding and Consensus’ 5, add:

[NU7 onward] fee MUST be in the range \(\{ 0 .. \mathsf{MAX\_MONEY} \}\) .

Signature Hash

The transaction signature hashing algorithm defined in ZIP 244 is to be modified for v6 transactions as follows:

Section T.1: header_digest 10 is specified in draft-txv6-sighash 11 to read:

A BLAKE2b-256 hash of the following values

T.1a: version             (4-byte little-endian version identifier including ``fOverwintered`` flag)
T.1b: version_group_id    (4-byte little-endian version group identifier)
T.1c: consensus_branch_id (4-byte little-endian consensus branch id)
T.1d: lock_time           (4-byte little-endian ``nLockTime`` value)
T.1e: expiry_height       (4-byte little-endian block height)
T.1f: fee                 (8-byte little-endian fee value)

The personalization field of this hash is set to:

"ZTxIdHeadersHash"

Applicability

All of these changes apply identically to Mainnet and Testnet.