representing body hash as buffer in TS

yarn-project/circuits.js/src/structs/header.test.ts

@@ -0,0 +1,12 @@
+import { makeHeader } from '../tests/factories.js';
+import { Header } from './header.js';
+
+describe('Header', () => {
+  it(`serializes to buffer and deserializes it back`, () => {
+    const randomInt = Math.floor(Math.random() * 1000);
+    const expected = makeHeader(randomInt, undefined);
+    const buffer = expected.toBuffer();
+    const res = Header.fromBuffer(buffer);
+    expect(res).toEqual(expected);
+  });
+});

yarn-project/circuits.js/src/structs/header.ts

@@ -1,23 +1,27 @@
-import { Fr } from '@aztec/foundation/fields';
 import { BufferReader, serializeToBuffer } from '@aztec/foundation/serialize';
 
-import { NUM_FIELDS_PER_SHA256 } from '../constants.gen.js';
 import { GlobalVariables } from './global_variables.js';
 import { AppendOnlyTreeSnapshot } from './rollup/append_only_tree_snapshot.js';
 import { StateReference } from './state_reference.js';
 
+export const NUM_BYTES_PER_SHA256 = 32;
+
 /** A header of an L2 block. */
 export class Header {
   constructor(
     /** Snapshot of archive before the block is applied. */
     public lastArchive: AppendOnlyTreeSnapshot,
     /** Hash of the body of an L2 block. */
-    public bodyHash: [Fr, Fr],
+    public bodyHash: Buffer,
     /** State reference. */
     public state: StateReference,
     /** Global variables of an L2 block. */
     public globalVariables: GlobalVariables,
-  ) {}
+  ) {
+    if (bodyHash.length !== 32) {
+      throw new Error('Body hash buffer must be 32 bytes');
+    }
+  }
 
   toBuffer() {
     // Note: The order here must match the order in the HeaderDecoder solidity library.
@@ -28,7 +32,7 @@ export class Header {
     const reader = BufferReader.asReader(buffer);
     return new Header(
       reader.readObject(AppendOnlyTreeSnapshot),
-      reader.readArray(NUM_FIELDS_PER_SHA256, Fr) as [Fr, Fr],
+      reader.readBytes(NUM_BYTES_PER_SHA256),
       reader.readObject(StateReference),
       reader.readObject(GlobalVariables),
     );

yarn-project/circuits.js/src/structs/rollup/root_rollup.ts

@@ -95,23 +95,6 @@ export class RootRollupPublicInputs {
     return new RootRollupPublicInputs(...RootRollupPublicInputs.getFields(fields));
   }
 
-  /**
-   * Returns the sha256 hash of the calldata.
-   * @returns The sha256 hash of the calldata.
-   */
-  public sha256CalldataHash(): Buffer {
-    const high = this.header.bodyHash[0].toBuffer();
-    const low = this.header.bodyHash[1].toBuffer();
-
-    const hash = Buffer.alloc(32);
-    for (let i = 0; i < 16; i++) {
-      hash[i] = high[i + 16];
-      hash[i + 16] = low[i + 16];
-    }
-
-    return hash;
-  }
-
   /**
    * Deserializes a buffer into a `RootRollupPublicInputs` object.
    * @param buffer - The buffer to deserialize.

yarn-project/circuits.js/src/tests/factories.ts

@@ -3,6 +3,8 @@ import { AztecAddress } from '@aztec/foundation/aztec-address';
 import { EthAddress } from '@aztec/foundation/eth-address';
 import { numToUInt32BE } from '@aztec/foundation/serialize';
 
+import { randomBytes } from 'crypto';
+
 import { SchnorrSignature } from '../barretenberg/index.js';
 import {
   ARCHIVE_HEIGHT,
@@ -101,7 +103,7 @@ import {
   WitnessedPublicCallData,
 } from '../index.js';
 import { GlobalVariables } from '../structs/global_variables.js';
-import { Header } from '../structs/header.js';
+import { Header, NUM_BYTES_PER_SHA256 } from '../structs/header.js';
 
 /**
  * Creates an arbitrary side effect object with the given seed.
@@ -882,7 +884,7 @@ export function makeRootRollupPublicInputs(
 export function makeHeader(seed = 0, globalVariables: GlobalVariables | undefined): Header {
   return new Header(
     makeAppendOnlyTreeSnapshot(seed + 0x100),
-    [new Fr(5n), new Fr(6n)],
+    randomBytes(NUM_BYTES_PER_SHA256),
     makeStateReference(seed + 0x200),
     globalVariables ?? makeGlobalVariables((seed += 0x100)),
   );

yarn-project/noir-protocol-circuits/src/type_conversion.ts

@@ -72,7 +72,7 @@ import {
   TxContext,
   TxRequest,
 } from '@aztec/circuits.js';
-import { Tuple, mapTuple } from '@aztec/foundation/serialize';
+import { Tuple, from2Fields, mapTuple } from '@aztec/foundation/serialize';
 
 import {
   BlockHeader as BlockHeaderNoir,
@@ -137,6 +137,8 @@ import {
   AppendOnlyTreeSnapshot as AppendOnlyTreeSnapshotNoir,
   BaseOrMergeRollupPublicInputs as BaseOrMergeRollupPublicInputsNoir,
   ConstantRollupData as ConstantRollupDataNoir,
+  Field,
+  FixedLengthArray,
   GlobalVariables as GlobalVariablesNoir,
   Header as HeaderNoir,
   PartialStateReference as PartialStateReferenceNoir,
@@ -678,6 +680,15 @@ export function mapTupleFromNoir<T, N extends number, M>(
   return Array.from({ length }, (_, idx) => mapper(noirArray[idx])) as Tuple<M, N>;
 }
 
+/**
+ * Maps a SHA256 hash from noir to the parsed type.
+ * @param hash - The hash as it is represented in Noir (2 fields).
+ * @returns The hash represented as a 32 bytes long buffer.
+ */
+export function mapSha256HashFromNoir(hash: FixedLengthArray<Field, 2>): Buffer {
+  return from2Fields(mapFieldFromNoir(hash[0]), mapFieldFromNoir(hash[1]));
+}
+
 /**
  * Maps optionally revealed data from noir to the parsed type.
  * @param optionallyRevealedData - The noir optionally revealed data.
@@ -1318,7 +1329,7 @@ export function mapRootRollupPublicInputsFromNoir(
 export function mapHeaderFromNoir(header: HeaderNoir): Header {
   return new Header(
     mapAppendOnlyTreeSnapshotFromNoir(header.last_archive),
-    mapTupleFromNoir(header.body_hash, 2, mapFieldFromNoir),
+    mapSha256HashFromNoir(header.body_hash),
     mapStateReferenceFromNoir(header.state),
     mapGlobalVariablesFromNoir(header.global_variables),
   );

yarn-project/sequencer-client/src/block_builder/solo_block_builder.ts

@@ -144,7 +144,7 @@ export class SoloBlockBuilder implements BlockBuilder {
       newUnencryptedLogs,
     });
 
-    if (!l2Block.getCalldataHash().equals(circuitsOutput.sha256CalldataHash())) {
+    if (!l2Block.getCalldataHash().equals(circuitsOutput.header.bodyHash)) {
       throw new Error(
         `Calldata hash mismatch, ${l2Block.getCalldataHash().toString('hex')} == ${circuitsOutput
           .sha256CalldataHash()