Hide a field after form has been submitted

Hi,

I'm wondering if anyone knows if this is possible... I want one of my fields to be entered by a user, but after the user submits the form, I'd like the field (and its entry) to be hidden from the Submission. I'd still like it to be submitted as part of the initial submission, but would like it hidden from future viewing.

Reasoning... this field will contain sensitive data that only needs to be collected once. To avoid security issues down the road, it would be best if this field "disappears" after the initial submission.