From the users mailing list...

Hi Christian,

I guess the value of the field was null when it's rendered, wasn't it?
It seems that encrypted field must have a non-null value when it is
rendered.

In my last project, I removed the field when the value is null to
workaround the issue.

<c:if test="${!empty actionBean.user.id}">
<stripes:hidden name="user.id" />
</c:if>

--
IMHO, it would be nice if null value is encrypted in the same way as
normal value because I often use the same form for both editing an
existing instance and creating a new instance (as most of you, I suppose).
Any thoughts?

Regards,
Iwao