Batch convert commitments/proofs to bytes (#626)

Author: jtraglia

src/eip4844/eip4844.c

@@ -604,6 +604,8 @@ static C_KZG_RET compute_r_powers_for_verify_kzg_proof_batch(
 ) {
     C_KZG_RET ret;
     uint8_t *bytes = NULL;
+    blst_p1_affine *commitments_affine = NULL;
+    blst_p1_affine *proofs_affine = NULL;
     Bytes32 r_bytes;
     fr_t r;
 
@@ -613,6 +615,18 @@ static C_KZG_RET compute_r_powers_for_verify_kzg_proof_batch(
     ret = c_kzg_malloc((void **)&bytes, input_size);
     if (ret != C_KZG_OK) goto out;
 
+    /* Allocate space for affine commitments and proofs */
+    ret = c_kzg_malloc((void **)&commitments_affine, n * sizeof(blst_p1_affine));
+    if (ret != C_KZG_OK) goto out;
+    ret = c_kzg_malloc((void **)&proofs_affine, n * sizeof(blst_p1_affine));
+    if (ret != C_KZG_OK) goto out;
+
+    /* Batch convert commitments and proofs to affine */
+    const blst_p1 *commitments_arg[2] = {commitments_g1, NULL};
+    blst_p1s_to_affine(commitments_affine, commitments_arg, n);
+    const blst_p1 *proofs_arg[2] = {proofs_g1, NULL};
+    blst_p1s_to_affine(proofs_affine, proofs_arg, n);
+
     /* Pointer tracking `bytes` for writing on top of it */
     uint8_t *offset = bytes;
 
@@ -633,7 +647,7 @@ static C_KZG_RET compute_r_powers_for_verify_kzg_proof_batch(
 
     for (size_t i = 0; i < n; i++) {
         /* Copy commitment */
-        bytes_from_g1((Bytes48 *)offset, &commitments_g1[i]);
+        blst_p1_affine_compress(offset, &commitments_affine[i]);
         offset += BYTES_PER_COMMITMENT;
 
         /* Copy z */
@@ -645,7 +659,7 @@ static C_KZG_RET compute_r_powers_for_verify_kzg_proof_batch(
         offset += BYTES_PER_FIELD_ELEMENT;
 
         /* Copy proof */
-        bytes_from_g1((Bytes48 *)offset, &proofs_g1[i]);
+        blst_p1_affine_compress(offset, &proofs_affine[i]);
         offset += BYTES_PER_PROOF;
     }
 
@@ -660,6 +674,8 @@ static C_KZG_RET compute_r_powers_for_verify_kzg_proof_batch(
 
 out:
     c_kzg_free(bytes);
+    c_kzg_free(commitments_affine);
+    c_kzg_free(proofs_affine);
     return ret;
 }
 

src/eip7594/eip7594.c

@@ -65,6 +65,7 @@ C_KZG_RET compute_cells_and_kzg_proofs(
     fr_t *poly_lagrange = NULL;
     fr_t *data_fr = NULL;
     g1_t *proofs_g1 = NULL;
+    blst_p1_affine *proofs_affine = NULL;
 
     /* If both of these are null, something is wrong */
     if (cells == NULL && proofs == NULL) {
@@ -131,9 +132,17 @@ C_KZG_RET compute_cells_and_kzg_proofs(
         ret = bit_reversal_permutation(proofs_g1, sizeof(g1_t), CELLS_PER_EXT_BLOB);
         if (ret != C_KZG_OK) goto out;
 
-        /* Convert all of the proofs to byte-form */
+        /* Allocate space for affine proofs */
+        ret = c_kzg_malloc((void **)&proofs_affine, CELLS_PER_EXT_BLOB * sizeof(blst_p1_affine));
+        if (ret != C_KZG_OK) goto out;
+
+        /* Batch convert proofs to affine */
+        const blst_p1 *proofs_arg[2] = {proofs_g1, NULL};
+        blst_p1s_to_affine(proofs_affine, proofs_arg, CELLS_PER_EXT_BLOB);
+
+        /* Compress all of the proofs to byte-form */
         for (size_t i = 0; i < CELLS_PER_EXT_BLOB; i++) {
-            bytes_from_g1(&proofs[i], &proofs_g1[i]);
+            blst_p1_affine_compress(proofs[i].bytes, &proofs_affine[i]);
         }
     }
 
@@ -142,6 +151,7 @@ C_KZG_RET compute_cells_and_kzg_proofs(
     c_kzg_free(poly_lagrange);
     c_kzg_free(data_fr);
     c_kzg_free(proofs_g1);
+    c_kzg_free(proofs_affine);
     return ret;
 }
 
@@ -174,6 +184,7 @@ C_KZG_RET recover_cells_and_kzg_proofs(
     C_KZG_RET ret;
     fr_t *recovered_cells_fr = NULL;
     g1_t *recovered_proofs_g1 = NULL;
+    blst_p1_affine *recovered_proofs_affine = NULL;
 
     /* Ensure only one blob's worth of cells was provided */
     if (num_cells > CELLS_PER_EXT_BLOB) {
@@ -268,15 +279,26 @@ C_KZG_RET recover_cells_and_kzg_proofs(
         ret = bit_reversal_permutation(recovered_proofs_g1, sizeof(g1_t), CELLS_PER_EXT_BLOB);
         if (ret != C_KZG_OK) goto out;
 
-        /* Convert all of the proofs to byte-form */
+        /* Allocate space for affine proofs */
+        ret = c_kzg_malloc(
+            (void **)&recovered_proofs_affine, CELLS_PER_EXT_BLOB * sizeof(blst_p1_affine)
+        );
+        if (ret != C_KZG_OK) goto out;
+
+        /* Batch convert proofs to affine */
+        const blst_p1 *recovered_proofs_arg[2] = {recovered_proofs_g1, NULL};
+        blst_p1s_to_affine(recovered_proofs_affine, recovered_proofs_arg, CELLS_PER_EXT_BLOB);
+
+        /* Compress all of the proofs to byte-form */
         for (size_t i = 0; i < CELLS_PER_EXT_BLOB; i++) {
-            bytes_from_g1(&recovered_proofs[i], &recovered_proofs_g1[i]);
+            blst_p1_affine_compress(recovered_proofs[i].bytes, &recovered_proofs_affine[i]);
         }
     }
 
 out:
     c_kzg_free(recovered_cells_fr);
     c_kzg_free(recovered_proofs_g1);
+    c_kzg_free(recovered_proofs_affine);
     return ret;
 }