minor update to test, challenge instantiation

AztecProtocol · Oct 5, 2023 · 2e55921 · 2e55921
1 parent 6eaa1a3
commit 2e55921
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Showing 2 changed files with 21 additions and 3 deletions.
diff --git a/barretenberg/cpp/src/barretenberg/honk/transcript/transcript.hpp b/barretenberg/cpp/src/barretenberg/honk/transcript/transcript.hpp
@@ -168,9 +168,10 @@ template <typename FF> class BaseTranscript {
         for (size_t i = 0; i < num_challenges; i++) {
             auto next_challenge_buffer = get_next_challenge_buffer(); // get next challenge buffer
             std::array<uint8_t, sizeof(FF)> field_element_buffer{};
-            std::copy_n(next_challenge_buffer.begin(), HASH_OUTPUT_SIZE, field_element_buffer.begin());
-            // set upper half to 0 to make challenge 128 bits
-            std::fill_n(field_element_buffer.begin(), HASH_OUTPUT_SIZE / 2, 0);
+            // copy half of the hash to lower 128 bits of challenge
+            std::copy_n(next_challenge_buffer.begin(),
+                        HASH_OUTPUT_SIZE / 2,
+                        field_element_buffer.begin() + HASH_OUTPUT_SIZE / 2);
             challenges[i] = from_buffer<FF>(field_element_buffer);
         }
 

diff --git a/barretenberg/cpp/src/barretenberg/honk/transcript/transcript.test.cpp b/barretenberg/cpp/src/barretenberg/honk/transcript/transcript.test.cpp
@@ -185,15 +185,32 @@ TEST_F(UltraTranscriptTests, VerifierManifestConsistency)
     }
 }
 
+/**
+ * @brief Check that multiple challenges can be generated and sanity check
+ * @details We generate 6 challenges that are each 128 bits, and check that they are not 0.
+ *
+ */
 TEST_F(UltraTranscriptTests, ChallengeGenerationTest)
 {
+    // initialized with random value sent to verifier
     auto transcript = ProverTranscript<FF>::init_empty();
+    // test a bunch of challenges
     auto challenges = transcript.get_challenges("a", "b", "c", "d", "e", "f");
     // print challenges and check they are not 0
     for (size_t i = 0; i < challenges.size(); ++i) {
         info("Challenge ", i, ": ", challenges[i]);
         ASSERT_NE(challenges[i], 0) << "Challenge " << i << " is 0";
     }
+    constexpr uint32_t random_val{ 17 }; // arbitrary
+    transcript.send_to_verifier("random val", random_val);
+    // test more challenges
+    auto [a, b, c] = transcript.get_challenges("a", "b", "c");
+    info("Challenge a: ", a);
+    info("Challenge b: ", b);
+    info("Challenge c: ", c);
+    ASSERT_NE(a, 0) << "Challenge a is 0";
+    ASSERT_NE(b, 0) << "Challenge a is 0";
+    ASSERT_NE(b, 0) << "Challenge a is 0";
 }
 
 TEST_F(UltraTranscriptTests, FoldingManifestTest)