Reduce the timing tests complexity
diff --git a/ChangeLog b/ChangeLog
index 5cfd9a2..096be45 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -22,6 +22,8 @@
      Inserted as an enhancement for #1371
    * Add support for alternative CSR headers, as used by Microsoft and defined
      in RFC 7468. Found by Michael Ernst. Fixes #767.
+   * Reduced the complexity of the timing tests, as they were failing in less
+     reliable environments.
 
 = mbed TLS 2.16.0 branch released 2018-12-21