commit 1a7c5ef42bc6b1a5e6a6cd6ba9c014d8e7163ad2
author Manuel Pégourié-Gonnard <mpg2@elzevir.fr> Thu Aug 13 10:19:09 2015 +0200
committer Manuel Pégourié-Gonnard <mpg2@elzevir.fr> Mon Sep 07 12:43:10 2015 +0200
tree 0afee86c9ae644a840d57aedb2abdaa600ad69f3
parent cb7cd03412f51ce5d0caa240a35fe47e5bc4488e

Optimize some case of mbedtls_ecp_muladd()

Those are used by EC-JPAKE

library/ecp.c

diff --git a/library/ecp.c b/library/ecp.c
index 54f51ab..89a5612 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -1697,8 +1697,17 @@
 
     mbedtls_ecp_point_init( &mP );
 
-    MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, &mP, m, P, NULL, NULL ) );
-    MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R,   n, Q, NULL, NULL ) );
+    /* Optimize some simple special cases */
+    if( mbedtls_mpi_cmp_int( m, 1 ) == 0 )
+        MBEDTLS_MPI_CHK( mbedtls_ecp_copy( &mP, P ) );
+    else
+        MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, &mP, m, P, NULL, NULL ) );
+
+    if( mbedtls_mpi_cmp_int( n, 1 ) == 0 )
+        MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, Q ) );
+    else
+        MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, R,   n, Q, NULL, NULL ) );
+
     MBEDTLS_MPI_CHK( ecp_add_mixed( grp, R, &mP, R ) );
     MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, R ) );