Merge pull request #10 from ecnerwala/rangecheckmod

BigMod incorrectly omits range checks on the remainder
0xPARC · Apr 27, 2022 · 08c2c90 · 08c2c90
2 parents 14ad152 + d3edd75
commit 08c2c90
Showing 1 changed file with 8 additions and 3 deletions.
diff --git a/circuits/bigint.circom b/circuits/bigint.circom
@@ -374,10 +374,15 @@ template BigMod(n, k) {
         mod[i] <-- longdiv[1][i];
     }
     div[k] <-- longdiv[0][k];
-    component range_checks[k + 1];
+    component div_range_checks[k + 1];
     for (var i = 0; i <= k; i++) {
-        range_checks[i] = Num2Bits(n);
-        range_checks[i].in <== div[i];
+        div_range_checks[i] = Num2Bits(n);
+        div_range_checks[i].in <== div[i];
+    }
+    component mod_range_checks[k];
+    for (var i = 0; i < k; i++) {
+        mod_range_checks[i] = Num2Bits(n);
+        mod_range_checks[i].in <== mod[i];
     }
 
     component mul = BigMult(n, k + 1);