diff --git a/tests/suites/test_suite_base64.function b/tests/suites/test_suite_base64.function
index dc6ec15..ec10033 100644
--- a/tests/suites/test_suite_base64.function
+++ b/tests/suites/test_suite_base64.function
@@ -1,5 +1,6 @@
 /* BEGIN_HEADER */
 #include "mbedtls/base64.h"
+#include <test/constant_flow.h>
 /* END_HEADER */
 
 /* BEGIN_DEPENDENCIES
@@ -13,13 +14,18 @@
 {
     unsigned char src_str[1000];
     unsigned char dst_str[1000];
-    size_t len;
+    size_t len, src_len;
 
     memset(src_str, 0x00, 1000);
     memset(dst_str, 0x00, 1000);
 
     strncpy( (char *) src_str, src_string, sizeof(src_str) - 1 );
-    TEST_ASSERT( mbedtls_base64_encode( dst_str, dst_buf_size, &len, src_str, strlen( (char *) src_str ) ) == result );
+    src_len = strlen( (char *) src_str );
+
+    TEST_CF_SECRET( src_str, sizeof( src_str ) );
+    TEST_ASSERT( mbedtls_base64_encode( dst_str, dst_buf_size, &len, src_str, src_len) == result );
+    TEST_CF_PUBLIC( src_str, sizeof( src_str ) );
+
     if( result == 0 )
     {
         TEST_ASSERT( strcmp( (char *) dst_str, dst_string ) == 0 );
@@ -57,7 +63,10 @@
 
     res = mbedtls_test_zero_alloc( dst_buf_size );
 
+    TEST_CF_SECRET( src->x, src->len );
     TEST_ASSERT( mbedtls_base64_encode( res, dst_buf_size, &len, src->x, src->len ) == result );
+    TEST_CF_PUBLIC( src->x, src->len );
+
     if( result == 0 )
     {
         TEST_ASSERT( len == strlen( dst ) );