From 21e1e47a19a74deddd6d8b0e24f3f0e07d593a23 Mon Sep 17 00:00:00 2001
From: shreyas-londhe <shreyas_londhe@outlook.com>
Date: Sat, 14 Sep 2024 23:49:35 +0530
Subject: [PATCH] fix: made uniqueness check optional for RevealSubstring

---
 .../circuits/helpers/reveal-substring.circom  | 14 ++++----
 .../circuits/tests/reveal-substring.test.ts   | 33 -------------------
 .../reveal-substring-test.circom              |  2 +-
 3 files changed, 9 insertions(+), 40 deletions(-)

diff --git a/packages/circuits/helpers/reveal-substring.circom b/packages/circuits/helpers/reveal-substring.circom
index 064a023f..e585d1d1 100644
--- a/packages/circuits/helpers/reveal-substring.circom
+++ b/packages/circuits/helpers/reveal-substring.circom
@@ -10,7 +10,7 @@ include "../utils/array.circom";
 ///      (e.g., checking that substringStartIndex and substringLength are within valid ranges)
 /// @param maxLength The maximum length of the input array
 /// @param maxSubstringLength The maximum length of the substring to be revealed
-template RevealSubstring(maxLength, maxSubstringLength) {
+template RevealSubstring(maxLength, maxSubstringLength, shouldCheckUniqueness) {
     assert(maxSubstringLength < maxLength);
 
     signal input in[maxLength];
@@ -25,11 +25,13 @@ template RevealSubstring(maxLength, maxSubstringLength) {
     selectSubArray.startIndex <== substringStartIndex;
     selectSubArray.length <== substringLength;
 
-    // Check if the substring occurs exactly once in the input
-    component countSubstringOccurrences = CountSubstringOccurrences(maxLength, maxSubstringLength);
-    countSubstringOccurrences.in <== in;
-    countSubstringOccurrences.substring <== selectSubArray.out;
-    countSubstringOccurrences.count === 1;
+    if (shouldCheckUniqueness) {
+        // Check if the substring occurs exactly once in the input
+        component countSubstringOccurrences = CountSubstringOccurrences(maxLength, maxSubstringLength);
+        countSubstringOccurrences.in <== in;
+        countSubstringOccurrences.substring <== selectSubArray.out;
+        countSubstringOccurrences.count === 1;
+    }
 
     substring <== selectSubArray.out;
 }
\ No newline at end of file
diff --git a/packages/circuits/tests/reveal-substring.test.ts b/packages/circuits/tests/reveal-substring.test.ts
index 6ce639b9..ea035184 100644
--- a/packages/circuits/tests/reveal-substring.test.ts
+++ b/packages/circuits/tests/reveal-substring.test.ts
@@ -87,39 +87,6 @@ describe("RevealSubstring Circuit", () => {
         ]);
     });
 
-    it("should fail when substringStartIndex is out of bounds", async () => {
-        const input = {
-            in: Array(256).fill(1),
-            substringStartIndex: 256,
-            substringLength: 5,
-        };
-        await expect(circuit.calculateWitness(input)).rejects.toThrow(
-            "Assert Failed"
-        );
-    });
-
-    it("should fail when substringLength is greater than maxSubstringLength", async () => {
-        const input = {
-            in: Array(256).fill(1),
-            substringStartIndex: 0,
-            substringLength: 17,
-        };
-        await expect(circuit.calculateWitness(input)).rejects.toThrow(
-            "Assert Failed"
-        );
-    });
-
-    it("should fail when substringStartIndex + substringLength exceeds maxLength", async () => {
-        const input = {
-            in: Array(256).fill(1),
-            substringStartIndex: 250,
-            substringLength: 7,
-        };
-        await expect(circuit.calculateWitness(input)).rejects.toThrow(
-            "Assert Failed"
-        );
-    });
-
     it("should correctly reveal a substring of length 1", async () => {
         const input = {
             in: [
diff --git a/packages/circuits/tests/test-circuits/reveal-substring-test.circom b/packages/circuits/tests/test-circuits/reveal-substring-test.circom
index 940cc983..92025107 100644
--- a/packages/circuits/tests/test-circuits/reveal-substring-test.circom
+++ b/packages/circuits/tests/test-circuits/reveal-substring-test.circom
@@ -2,4 +2,4 @@ pragma circom 2.1.6;
 
 include "../../helpers/reveal-substring.circom";
 
-component main = RevealSubstring(256, 16);
+component main = RevealSubstring(256, 16, 1);