Fix little-endian serialization in compute_challenge() (#168)

2023-03-02 20:35:37 +02:00 · 2023-03-02 20:35:37 +02:00 · 53b38face0
parent ae0aeaf33d
commit 53b38face0
4 changed files with 6 additions and 7 deletions
--- a/src/c_kzg_4844.c
+++ b/src/c_kzg_4844.c
@ -722,12 +722,11 @@ static void compute_challenge(
    /* Copy domain separator */
    memcpy(offset, FIAT_SHAMIR_PROTOCOL_DOMAIN, 16);
    offset += 16;
-    bytes_from_uint64(
-        offset, 0
-    ); /* need to fill 16 bytes with the degree in little-endian */
-    offset += 8;
    bytes_from_uint64(offset, FIELD_ELEMENTS_PER_BLOB);
    offset += 8;
+    /* Set all other bytes of this 16-byte (little-endian) field to zero */
+    bytes_from_uint64(offset, 0);
+    offset += 8;

    /* Copy blob */
    memcpy(offset, blob->bytes, BYTES_PER_BLOB);
--- a/tests/compute_blob_kzg_proof/success/proof.txt
+++ b/tests/compute_blob_kzg_proof/success/proof.txt
@ -1 +1 @@
-a1b505e8e7e1779eb2077464f5d793e4f36e5060970797c936370266095d048976557826ae0397d7d70256aff13cc6b0
+9057e4724ea7b27acaae09b56155c86452a3c034b049d2d13fc2701845d2dcfa8d33612c1f9ecbaba7f7a920458eb5b8
--- a/tests/verify_blob_kzg_proof/success/ok.txt
+++ b/tests/verify_blob_kzg_proof/success/ok.txt
@ -1 +1 @@
-true
+false
--- a/tests/verify_blob_kzg_proof_batch/success/ok.txt
+++ b/tests/verify_blob_kzg_proof_batch/success/ok.txt
@ -1 +1 @@
-true
+false