From 8f6bc22b2f9e41da835911069af1eb3191749d41 Mon Sep 17 00:00:00 2001
From: Ramana Kumar <ramana@member.fsf.org>
Date: Sat, 1 Oct 2022 12:42:44 +0100
Subject: [PATCH] Avoid exposing blst scalar

---
 min-bindings/c_kzg_4844.swg | 1 -
 min-src/c_kzg_4844.c        | 8 +++++---
 min-src/c_kzg_4844.h        | 5 ++---
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/min-bindings/c_kzg_4844.swg b/min-bindings/c_kzg_4844.swg
index 25a3e71..f435dc2 100644
--- a/min-bindings/c_kzg_4844.swg
+++ b/min-bindings/c_kzg_4844.swg
@@ -70,7 +70,6 @@
 }
 #endif
 
-%array_class(scalar_t, scalars)
 %array_class(uint8_t, bytes)
 %array_class(BLSFieldElement, BLSFieldElements)
 %pointer_class(PolynomialEvalForm, PolynomialEvalFormPtr)
diff --git a/min-src/c_kzg_4844.c b/min-src/c_kzg_4844.c
index 4af0cc6..5c40cd5 100644
--- a/min-src/c_kzg_4844.c
+++ b/min-src/c_kzg_4844.c
@@ -753,7 +753,7 @@ static bool pairings_verify(const g1_t *a1, const g2_t *a2, const g1_t *b1, cons
 }
 
 
-void Bytes48_from_G1(uint8_t out[48], const g1_t *in) {
+void bytes_from_G1(uint8_t out[48], const g1_t *in) {
   blst_p1_compress(out, in);
 }
 
@@ -824,8 +824,10 @@ void compute_powers(fr_t out[], const fr_t *x, uint64_t n) {
     while (++i < n) fr_mul(&out[i], &out[i-1], x);
 }
 
-void bytes_to_bls_field(BLSFieldElement *out, const scalar_t *bytes) {
-  blst_fr_from_scalar(out, bytes);
+void bytes_to_bls_field(BLSFieldElement *out, const uint8_t bytes[32]) {
+  blst_scalar tmp;
+  blst_scalar_from_lendian(&tmp, bytes);
+  blst_fr_from_scalar(out, &tmp);
 }
 
 /**
diff --git a/min-src/c_kzg_4844.h b/min-src/c_kzg_4844.h
index 23162fa..9b4b369 100644
--- a/min-src/c_kzg_4844.h
+++ b/min-src/c_kzg_4844.h
@@ -32,7 +32,6 @@
 typedef blst_p1 g1_t;         /**< Internal G1 group element type */
 typedef blst_p2 g2_t;         /**< Internal G2 group element type */
 typedef blst_fr fr_t;         /**< Internal Fr field element type */
-typedef blst_scalar scalar_t; /**< Internal scalar type */
 
 typedef g1_t KZGCommitment;
 typedef g1_t KZGProof;
@@ -41,7 +40,7 @@ typedef fr_t BLSFieldElement;
 /**
  * KZGCommitment and KZGProof can be recovered as 48 bytes
  */
-void Bytes48_from_G1(uint8_t out[48], const g1_t*);
+void bytes_from_G1(uint8_t out[48], const g1_t*);
 
 /**
  * BLSFieldElements are communicated directly to/from clients,
@@ -105,7 +104,7 @@ C_KZG_RET load_trusted_setup(KZGSettings *out, FILE *in);
 
 void free_trusted_setup(KZGSettings *s);
 
-void bytes_to_bls_field(BLSFieldElement *out, const scalar_t *bytes);
+void bytes_to_bls_field(BLSFieldElement *out, const uint8_t bytes[32]);
 
 void vector_lincomb(BLSFieldElement out[], const BLSFieldElement *vectors, const BLSFieldElement *scalars, uint64_t num_vectors, uint64_t vector_len);