commit 153ae464db633edd427339cbbcf529626b40d46d
author Chien Wong <m@xv97.com> Tue Jan 31 23:27:03 2023 +0800
committer Chien Wong <m@xv97.com> Mon Aug 07 23:02:31 2023 +0800
tree bc58b222ae4f9c2c274d5fe4221a9ce7ad902c64
parent 3b5e8aa05cc7e0bc6478143e8ad131df9bfce016

Improve doc on special use of A in ecp group structure

Signed-off-by: Chien Wong <m@xv97.com>

library/ecp.c

diff --git a/library/ecp.c b/library/ecp.c
index 870773c..f9b6672 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -1255,7 +1255,7 @@
     MPI_ECP_SQR(rhs, X);
 
     /* Special case for A = -3 */
-    if (grp->A.p == NULL) {
+    if (mbedtls_ecp_group_a_is_minus_3(grp)) {
         MPI_ECP_SUB_INT(rhs, rhs, 3);
     } else {
         MPI_ECP_ADD(rhs, rhs, &grp->A);
@@ -1526,7 +1526,7 @@
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
     /* Special case for A = -3 */
-    if (grp->A.p == NULL) {
+    if (mbedtls_ecp_group_a_is_minus_3(grp)) {
         /* tmp[0] <- M = 3(X + Z^2)(X - Z^2) */
         MPI_ECP_SQR(&tmp[1],  &P->Z);
         MPI_ECP_ADD(&tmp[2],  &P->X,  &tmp[1]);