fix for BitcoinDA - support fallback for 64 byte DA input

the DA input should fall back to check that it matches what the RollupL2DAValidator outputs (which is what the RollupL1DAValidator input expects and validates against) which is the 2 32 byte hashes of pubdata (DA for precompile) and state diff hash.

Author: jagdeep sidhu

da-contracts/contracts/CalldataDA.sol

@@ -69,8 +69,15 @@ abstract contract CalldataDA {
         uint256 ptr = BLOB_DATA_OFFSET + 32 * blobsProvided;
 
         // Now, we need to double check that the provided input was indeed returned by the L2 DA validator.
-        if (keccak256(_operatorDAInput[:ptr]) != _l2DAValidatorOutputHash) {
-            revert InvalidL2DAOutputHash(_l2DAValidatorOutputHash);
+        // SYSCOIN Accept either the full-header hash (preferred) or the short 64-byte variant used by some L2 DA validators.
+        {
+            bytes32 hFull = keccak256(_operatorDAInput[:ptr]);
+            if (hFull != _l2DAValidatorOutputHash) {
+                // Fallback: compare against the short (64-byte) prefix (stateDiffHash || fullPubdataHash).
+                if (keccak256(_operatorDAInput[:64]) != _l2DAValidatorOutputHash) {
+                    revert InvalidL2DAOutputHash(_l2DAValidatorOutputHash);
+                }
+            }
         }
 
         // The rest of the output was provided specifically by the operator

l1-contracts/contracts/state-transition/data-availability/CalldataDA.sol

@@ -69,8 +69,15 @@ abstract contract CalldataDA {
         uint256 ptr = BLOB_DATA_OFFSET + 32 * blobsProvided;
 
         // Now, we need to double check that the provided input was indeed returned by the L2 DA validator.
-        if (keccak256(_operatorDAInput[:ptr]) != _l2DAValidatorOutputHash) {
-            revert InvalidL2DAOutputHash(_l2DAValidatorOutputHash);
+        // SYSCOIN Accept either the full-header hash (preferred) or the short 64-byte variant used by some L2 DA validators.
+        {
+            bytes32 hFull = keccak256(_operatorDAInput[:ptr]);
+            if (hFull != _l2DAValidatorOutputHash) {
+                // Fallback: compare against the short (64-byte) prefix (stateDiffHash || fullPubdataHash).
+                if (keccak256(_operatorDAInput[:64]) != _l2DAValidatorOutputHash) {
+                    revert InvalidL2DAOutputHash(_l2DAValidatorOutputHash);
+                }
+            }
         }
 
         // The rest of the output was provided specifically by the operator

l1-contracts/test/foundry/l1/unit/concrete/state-transition/data-availability/CalldataDA.t.sol

@@ -112,6 +112,36 @@ contract CalldataDATest is Test {
         assertEq(blobsLinearHashes[0], blobLinearHash, "blobsLinearHashes");
         assertEq(outputL1DaInput, l1DaInput, "l1DaInput");
     }
+    // SYSCOIN
+    function test_ProcessL2RollupDAValidatorOutputHashWithShortHash() public {
+        bytes32 stateDiffHash = Utils.randomBytes32("stateDiffHash");
+        bytes32 fullPubdataHash = Utils.randomBytes32("fullPubdataHash");
+        uint8 blobsProvided = 1;
+        bytes32 blobLinearHash = Utils.randomBytes32("blobLinearHash");
+
+        bytes memory shortData = abi.encodePacked(stateDiffHash, fullPubdataHash);
+        bytes memory l1DaInput = "verifydonttrust";
+
+        // Use the short (64-byte) hash as the l2DAValidatorOutputHash
+        bytes32 l2DAValidatorOutputHash = keccak256(shortData);
+
+        // Full operator input includes all data
+        bytes memory operatorDAInput = abi.encodePacked(stateDiffHash, fullPubdataHash, blobsProvided, blobLinearHash, l1DaInput);
+
+        (
+            bytes32 outputStateDiffHash,
+            bytes32 outputFullPubdataHash,
+            bytes32[] memory blobsLinearHashes,
+            uint256 outputBlobsProvided,
+            bytes memory outputL1DaInput
+        ) = calldataDA.processL2RollupDAValidatorOutputHash(l2DAValidatorOutputHash, blobsProvided, operatorDAInput);
+
+        assertEq(outputStateDiffHash, stateDiffHash, "stateDiffHash");
+        assertEq(outputFullPubdataHash, fullPubdataHash, "fullPubdataHash");
+        assertEq(blobsLinearHashes.length, 1, "blobsLinearHashesLength");
+        assertEq(blobsLinearHashes[0], blobLinearHash, "blobsLinearHashes");
+        assertEq(outputL1DaInput, l1DaInput, "l1DaInput");
+    }
 
     /*//////////////////////////////////////////////////////////////////////////
                             CalldataDA::_processCalldataDA