Merge pull request #356 from EYBlockchain/hari/duplicate-commitment

Hari/duplicate commitment

nightfall-client/src/services/commitment-storage.mjs

@@ -456,7 +456,7 @@ async function findUsableCommitments(compressedPkd, ercAddress, tokenId, _value,
     return [singleCommitment];
   }
   // If we get here it means that we have not been able to find a single commitment that matches the required value
-  if (onlyOne) return null; // sometimes we require just one commitment
+  if (onlyOne || commitments.length < 2) return null; // sometimes we require just one commitment
 
   /* if not, maybe we can do a two-commitment transfer. The current strategy aims to prioritise smaller commitments while also
      minimising the creation of low value commitments (dust)
@@ -493,6 +493,7 @@ async function findUsableCommitments(compressedPkd, ercAddress, tokenId, _value,
   // then we will need to use a commitment of greater value than the target
   if (twoGreatestSum < value.bigInt) {
     if (commitsLessThanTargetValue.length === sortedCommits.length) return null; // We don't have any more commitments
+    if (commitsLessThanTargetValue.length === 0) return [sortedCommits[0], sortedCommits[1]]; // return smallest in GT if LT array is empty
     return [sortedCommits[commitsLessThanTargetValue.length], sortedCommits[0]]; // This should guarantee that we will replace our smallest commitment with a greater valued one.
   }
 

nightfall-optimist/src/services/transaction-checker.mjs

@@ -93,6 +93,7 @@ async function checkTransactionType(transaction) {
         transaction.commitments.length !== 2 ||
         transaction.nullifiers.some(n => n === ZERO) ||
         transaction.nullifiers.length !== 2 ||
+        transaction.nullifiers[0] === transaction.nullifiers[1] ||
         transaction.compressedSecrets.every(cs => cs === ZERO) ||
         transaction.compressedSecrets.length !== 8 ||
         transaction.proof.every(p => p === ZERO)