zcash · nuttycom · May 20, 2025 · Feb 4, 2025 · Feb 4, 2025 · Feb 11, 2025
diff --git a/README.template b/README.template
@@ -55,6 +55,7 @@ The following ZIPs are under consideration for inclusion in NU7:
 - `ZIP 233: Network Sustainability Mechanism: Burning <zip-0233.md>`__
 - `ZIP 234: Network Sustainability Mechanism: Issuance Smoothing <zip-0234.md>`__
 - `ZIP 235: Network Sustainability Mechanism: Burn 60% of Transaction Fees <zip-0235.md>`__
+- `ZIP 246: Digests for the Version 6 Transaction Format <zip-0246.rst>`__
 - `ZIP 2002: Explicit Fees <zip-2002.rst>`__
 - `ZIP 2003: Disallow version 4 transactions <zip-2003.rst>`__
 - `ZIP 2004: Remove the dependency of consensus on note encryption <zip-2004.rst>`__

diff --git a/static/css/style.css b/static/css/style.css
@@ -420,7 +420,7 @@ div.math {
   overflow-y: hidden;
   margin: 2.6rem 1rem 2.6rem 1rem;
   text-align: center;
-  padding: 0;
+  padding: 2rem;
 }
 
 a, a:visited {

diff --git a/zips/zip-0226.rst b/zips/zip-0226.rst
@@ -345,206 +345,14 @@ OrchardZSA Transaction Structure
 The transaction format for v6 transactions is described in ZIP 230 [#zip-0230]_.
 
 
-TxId Digest
-===========
-
-The transaction digest algorithm defined in ZIP 244 [#zip-0244]_ is modified by the OrchardZSA protocol to add a new branch for issuance information, along with modifications within the ``orchard_digest`` to account for the inclusion of the Asset Base.
-The details of these changes are described in this section, and highlighted using the ``[UPDATED FOR ZSA]`` or ``[ADDED FOR ZSA]`` text label. We omit the details of the sections that do not change for the OrchardZSA protocol.
-
-txid_digest
------------
-A BLAKE2b-256 hash of the following values::
-
-   T.1: header_digest       (32-byte hash output)
-   T.2: transparent_digest  (32-byte hash output)
-   T.3: sapling_digest      (32-byte hash output)
-   T.4: orchard_digest      (32-byte hash output)  [UPDATED FOR ZSA]
-   T.5: issuance_digest     (32-byte hash output)  [ADDED FOR ZSA]
-
-The personalization field remains the same as in ZIP 244 [#zip-0244]_.
-
-T.4: orchard_digest
-```````````````````
-When OrchardZSA Actions Groups are present in the transaction, this digest is a BLAKE2b-256 hash of the following values::
-
-    T.4a: orchard_action_groups_digest   (32-byte hash output)          [ADDED FOR ZSA]
-    T.4b: orchard_zsa_burn_digest        (32-byte hash output)          [ADDED FOR ZSA]
-    T.4c: valueBalanceOrchard            (64-bit signed little-endian)
-
-The personalization field of this hash is the same as in ZIP 244 [#zip-0244]_ ::
-
-    "ZTxIdOrchardHash"
-
-In the case that the transaction has no OrchardZSA Action Groups, ``orchard_digest`` is ::
-
-    BLAKE2b-256("ZTxIdOrchardHash", [])
-
-T.4a: orchard_action_groups_digest
-''''''''''''''''''''''''''''''''''
-
-A BLAKE2b-256 hash of the subset of OrchardZSA Action Groups information for all OrchardZSA Action Groups belonging to the transaction.
-For each Action Group, the following elements are included in the hash::
-
-    T.4a.i  : orchard_actions_compact_digest      (32-byte hash output)
-    T.4a.ii : orchard_actions_memos_digest        (32-byte hash output)
-    T.4a.iii: orchard_actions_noncompact_digest   (32-byte hash output)
-    T.4a.iv : flagsOrchard                        (1 byte)
-    T.4a.v  : anchorOrchard                       (32 bytes)
-    T.4a.vi : nAGExpiryHeight                     (4 bytes)
-
-The personalization field of this hash is set to::
-
-    "ZTxIdOrcActGHash"
-
-
-T.4a.i: orchard_actions_compact_digest
-......................................
-
-A BLAKE2b-256 hash of the subset of OrchardZSA Action information intended to be included in
-an updated version of the ZIP-307 [#zip-0307]_ ``CompactBlock`` format for all OrchardZSA
-Actions belonging to the Action Group. For each Action, the following elements are included
-in the hash::
-
-   T.4a.i.1 : nullifier            (field encoding bytes)
-   T.4a.i.2 : cmx                  (field encoding bytes)
-   T.4a.i.3 : ephemeralKey         (field encoding bytes)
-   T.4a.i.4 : encCiphertext[..84]  (First 84 bytes of field encoding)  [UPDATED FOR ZSA]
-
-The personalization field of this hash is the same as in ZIP 244::
-
-  "ZTxIdOrcActCHash"
-
-
-T.4a.ii: orchard_actions_memos_digest
-.....................................
-
-A BLAKE2b-256 hash of the subset of Orchard shielded memo field data for all OrchardZSA
-Actions belonging to the Action Group. For each Action, the following elements are included
-in the hash::
-
-    T.4a.ii.1: encCiphertext[84..596] (contents of the encrypted memo field)  [UPDATED FOR ZSA]
-
-The personalization field of this hash remains identical to ZIP 244::
-
-  "ZTxIdOrcActMHash"
-
-
-T.4a.iii: orchard_actions_noncompact_digest
-...........................................
-
-A BLAKE2b-256 hash of the remaining subset of OrchardZSA Action information **not** intended
-for inclusion in an updated version of the the ZIP 307 [#zip-0307]_ ``CompactBlock``
-format, for all OrchardZSA Actions belonging to the Action Group. For each Action,
-the following elements are included in the hash::
-
-   T.4a.iii.1 : cv                    (field encoding bytes)
-   T.4a.iii.2 : rk                    (field encoding bytes)
-   T.4a.iii.3 : encCiphertext[596..]  (post-memo suffix of field encoding)  [UPDATED FOR ZSA]
-   T.4a.iii.4 : outCiphertext         (field encoding bytes)
-
-The personalization field of this hash is defined identically to ZIP 244::
-
-    "ZTxIdOrcActNHash"
-
 
-T.4b: orchard_zsa_burn_digest
-'''''''''''''''''''''''''''''
-
-A BLAKE2b-256 hash of the data from the burn fields of the transaction. For each tuple in 
-the $\mathsf{assetBurn}$ set, the following elements are included in the hash::
-
-    T.4b.i : assetBase    (field encoding bytes)
-    T.4b.ii: valueBurn    (field encoding bytes)
-
-The personalization field of this hash is set to::
-
-    "ZTxIdOrcBurnHash"
-
-In case the transaction does not perform the burning of any Assets (i.e. the 
-$\mathsf{assetBurn}$ set is empty), the ''orchard_zsa_burn_digest'' is::
-
-    BLAKE2b-256("ZTxIdOrcBurnHash", [])
-
-T.4b.i: assetBase
-.................
-The Asset Base being burnt encoded as the 32-byte representation of a point on the 
-Pallas curve.
-
-T.4b.ii: valueBurn
-..................
-Value of the Asset Base being burnt encoded as little-endian 8-byte representation 
-of 64-bit unsigned integer (e.g. u64 in Rust) raw value.
-
-
-T.5: issuance_digest
-````````````````````
-The details of the computation of this value are in ZIP 227 [#zip-0227-txiddigest]_.
-
-Signature Digest 
-================
-
-The details of the changes to this algorithm are in ZIP 227 [#zip-0227-sigdigest]_.
-
-Authorizing Data Commitment
-===========================
-
-The transaction digest algorithm defined in ZIP 244 [#zip-0244-authcommitment]_ which commits to the authorizing data of a transaction is modified by the OrchardZSA protocol to have the structure specified in this section.
-There is a new branch added for issuance information, along with modifications within the ``orchard_auth_digest`` to account for the presence of Action Groups.
-
-We highlight the changes for the OrchardZSA protocol via the ``[UPDATED FOR ZSA]`` or ``[ADDED FOR ZSA]`` text label, and we omit the descriptions of the sections that do not change for the OrchardZSA protocol::
-
-    auth_digest
-    ├── transparent_scripts_digest
-    ├── sapling_auth_digest
-    ├── orchard_auth_digest         [UPDATED FOR ZSA]
-    └── issuance_auth_digest        [ADDED FOR ZSA]
-
-The pair (Transaction Identifier, Auth Commitment) constitutes a commitment to all the data of a serialized transaction that may be included in a block.
-
-auth_digest
------------
-A BLAKE2b-256 hash of the following values ::
-
-   A.1: transparent_scripts_digest (32-byte hash output)
-   A.2: sapling_auth_digest        (32-byte hash output)
-   A.3: orchard_auth_digest        (32-byte hash output)  [UPDATED FOR ZSA]
-   A.4: issuance_auth_digest       (32-byte hash output)  [ADDED FOR ZSA]
-
-The personalization field of this hash remains the same as in ZIP 244.
-
-
-A.3: orchard_auth_digest
-````````````````````````
-
-In the case that OrchardZSA Action Groups are present, this is a BLAKE2b-256 hash of the following values::
-
-    A.3a: orchard_action_groups_auth_digest  (32-byte hash output)  [ADDED FOR ZSA]
-    A.3b: bindingSigOrchard                  (field encoding bytes)
-
-The personalization field of this hash is the same as in ZIP 244, that is::
-
-    "ZTxAuthOrchaHash"
-
-In case that the transaction has no OrchardZSA Action Groups, ``orchard_auth_digest`` is::
-
-    BLAKE2b-256("ZTxAuthOrchaHash", [])
-
-A.3a: orchard_action_groups_auth_digest
-'''''''''''''''''''''''''''''''''''''''
-
-This is a BLAKE2b-256 hash of the ``proofsOrchard`` and ``spendAuthSigsOrchard`` fields of all OrchardZSA Action Groups belonging to the transaction::
-
-    A.3a.i:  proofsOrchard               (field encoding bytes)
-    A.3a.ii: spendAuthSigsOrchard        (field encoding bytes)
-
-The personalization field of this hash is set to::
-
-    "ZTxAuthOrcAGHash"
-
-A.4: issuance_auth_digest
-`````````````````````````
+Modifications relative to ZIP 244 [#zip-0244]_
+==============================================
 
-The details of the computation of this value are in ZIP 227 [#zip-0227-authcommitment]_.
+Relative to the sighash algorithm defined in ZIP 244 [#zip-0244]_, the sighash algorithm
+that applies to v6 transactions differs by altering the Orchard bundle within
+the tree hash to match the corresponding OrchardZSA changes. See ZIP 246 [#zip-0246]_
+for details.
 
 
 Security and Privacy Considerations
@@ -604,12 +412,11 @@ References
 .. [#zip-0227-consensus] `ZIP 227: Issuance of Zcash Shielded Assets: Specification: Consensus Rule Changes <zip-0227.html#specification-consensus-rule-changes>`_
 .. [#zip-0227-note-commitment-order] `ZIP 227: Issuance of Zcash Shielded Assets: Addition to the Note Commitment Tree <zip-0227.html#addition-to-the-note-commitment-tree>`_
 .. [#zip-0227-txiddigest] `ZIP 227: Issuance of Zcash Shielded Assets: TxId Digest - Issuance <zip-0227.html#txid-digest-issuance>`_
-.. [#zip-0227-sigdigest] `ZIP 227: Issuance of Zcash Shielded Assets: Signature Digest <zip-0227.html#signature-digest>`_
 .. [#zip-0227-authcommitment] `ZIP 227: Issuance of Zcash Shielded Assets: Authorizing Data Commitment <zip-0227.html#authorizing-data-commitment-issuance>`_
 .. [#zip-0227-orchardzsa-fee-calculation] `ZIP 227: Issuance of Zcash Shielded Assets: OrchardZSA Fee Calculation <zip-0227.html#orchardzsa-fee-calculation>`_
 .. [#zip-0230] `ZIP 230: Version 6 Transaction Format <zip-0230.html>`_
 .. [#zip-0244] `ZIP 244: Transaction Identifier Non-Malleability <zip-0244.html>`_
-.. [#zip-0244-authcommitment] `ZIP 244: Transaction Identifier Non-Malleability: Authorizing Data Commitment <zip-0244.html#authorizing-data-commitment>`_
+.. [#zip-0246] `ZIP 246: Digests for the Version 6 Transaction Format <zip-0246.html>`_
 .. [#zip-0307] `ZIP 307: Light Client Protocol for Payment Detection <zip-0307.rst>`_
 .. [#protocol-notes] `Zcash Protocol Specification, Version 2024.5.1 [NU6]. Section 3.2: Notes <protocol/protocol.pdf#notes>`_
 .. [#protocol-actions] `Zcash Protocol Specification, Version 2024.5.1 [NU6]. Section 3.7: Action Transfers and their Descriptions <protocol/protocol.pdf#actions>`_