Ignore zero entries on multi-proofs

Author: r0qs

circuits/presentationFieldsAuth.circom

@@ -99,13 +99,20 @@ template VerifyCredentialMultiField(cdl, ctl) {
 
 	// Verify whether the fields exists in the credential tree
 	component fieldHasher[m];
+	component zero[m];
 	component credtree = MerkleMultiProof(cdl);
+	signal s[m];
 	for (var i = 0; i < m; i++) {
+		zero[i] = IsZero();
+		zero[i].in <== fields[i][0];
+		s[i] <== 1 - zero[i].out;
+
 		fieldHasher[i] = CredentialLeafHasher();
 		fieldHasher[i].key <== fields[i][0];
 		fieldHasher[i].value <== fields[i][1];
 		fieldHasher[i].salt <== fields[i][2];
-		credtree.leaves[i] <== fieldHasher[i].out;
+
+		credtree.leaves[i] <== (fieldHasher[i].out)*s[i];
 		credtree.pathElements[i] <== pathFieldElements[i];
 		credtree.leafIndices[i] <== fieldIndices[i];
 	}

circuits/score.circom

@@ -6,28 +6,26 @@ include "presentationFieldsAuth.circom";
 
 // Verifies whether all credentials exists in the certree and
 // that each credential's field exists in the correspondent credential tree using merkle multiproof
-// @param `tagIdx` is the index of the tag Field in the credential
 // @param `gradeIdx` is the index of the grade Field in the credential
-// @param `m` is the number of leaves/fields to be proved in each credential tree (precise-proof)
+// @param `tagIdx` is the index of the tag Field in the credential
 // @param `n` is the number of credentials to be verified
 // @param `cdl` is the level of the credential tree
 // @param `ctl` is the level of the certree
 // Note:
 // - each leave of the certree contains a commitment to a credential tree root
 // - currently m must be the same for all credentials in the certree
 // - each leave of a credential tree has 3 fields: key, value and salt
-template Score(tagIdx, gradeIdx, m, n, cdl, ctl) {
-	assert(m > 1);
-
+template Score(gradeIdx, tagIdx, n, cdl, ctl) {
 	signal input certreeRoot;
 	signal input requiredTags[n];
 	signal input weights[n];
 	signal input result;
 
-	signal input nullifierHashes[n];
+	var m = 1 << cdl;
 	signal input fields[n][m][3];
 	signal input pathFieldElements[n][m];
 	signal input fieldIndices[n][m];
+	signal input nullifierHashes[n];
 	signal input credentialRoots[n];
 	signal input subjects[n];
 	signal input secrets[n];
@@ -44,7 +42,7 @@ template Score(tagIdx, gradeIdx, m, n, cdl, ctl) {
 		credAuth[i].certreeRoot <== certreeRoot;
 		credAuth[i].nullifierHash <== nullifierHashes[i];
 
-		// ensure tags match 
+		// ensure tags match
 		sameTags[i] = IsEqual();
 		sameTags[i].in[0] <== requiredTags[i];
 		sameTags[i].in[1] <== fields[i][tagIdx][1];

circuits/score12.circom

@@ -2,4 +2,4 @@ pragma circom 2.0.4;
 
 include "score.circom";
 
-component main {public [certreeRoot, requiredTags, weights, result]} = Score(0, 1, 2, 5, 4, 12);
+component main {public [certreeRoot, requiredTags, weights, result]} = Score(0, 1, 5, 4, 12);