diff --git a/programs/pkey/ecdh_curve25519.c b/programs/pkey/ecdh_curve25519.c
index da28c7d..a348eff 100644
--- a/programs/pkey/ecdh_curve25519.c
+++ b/programs/pkey/ecdh_curve25519.c
@@ -78,7 +78,7 @@
     if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func,
                                      &entropy,
                                      (const unsigned char *) pers,
-                                     sizeof pers)) != 0) {
+                                     sizeof(pers))) != 0) {
         mbedtls_printf(" failed\n  ! mbedtls_ctr_drbg_seed returned %d\n",
                        ret);
         goto exit;
diff --git a/programs/pkey/ecdsa.c b/programs/pkey/ecdsa.c
index 8f9867a..e5d2d44 100644
--- a/programs/pkey/ecdsa.c
+++ b/programs/pkey/ecdsa.c
@@ -77,7 +77,7 @@
     size_t len;
 
     if (mbedtls_ecp_point_write_binary(&key->grp, &key->Q,
-                                       MBEDTLS_ECP_PF_UNCOMPRESSED, &len, buf, sizeof buf) != 0) {
+                                       MBEDTLS_ECP_PF_UNCOMPRESSED, &len, buf, sizeof(buf)) != 0) {
         mbedtls_printf("internal error\n");
         return;
     }