diff --git a/programs/ssl/ssl_client1.c b/programs/ssl/ssl_client1.c
index b69c78e..8c99023 100644
--- a/programs/ssl/ssl_client1.c
+++ b/programs/ssl/ssl_client1.c
@@ -75,7 +75,7 @@
 {
     int ret, len, server_fd;
     unsigned char buf[1024];
-    char *pers = "ssl_client1";
+    const char *pers = "ssl_client1";
 
     entropy_context entropy;
     ctr_drbg_context ctr_drbg;
@@ -96,7 +96,8 @@
 
     entropy_init( &entropy );
     if( ( ret = ctr_drbg_init( &ctr_drbg, entropy_func, &entropy,
-                               (unsigned char *) pers, strlen( pers ) ) ) != 0 )
+                               (const unsigned char *) pers,
+                               strlen( pers ) ) ) != 0 )
     {
         printf( " failed\n  ! ctr_drbg_init returned %d\n", ret );
         goto exit;
@@ -111,7 +112,7 @@
     fflush( stdout );
 
 #if defined(POLARSSL_CERTS_C)
-    ret = x509parse_crt( &cacert, (unsigned char *) test_ca_crt,
+    ret = x509parse_crt( &cacert, (const unsigned char *) test_ca_crt,
                          strlen( test_ca_crt ) );
 #else
     ret = 1;