Is it possible to store Active Directory credentials as a token for an user in the domain using only a Forms Public Portal license, but without a named user or authenticated user license?

In this situation a couple thousand users need to complete HR policy forms, and agree to them through the Forms Portal. But it is critical that the Active Directory token information is written to the resulting document, showing who signed it and when.

To be clear, it is understood that this is possible with a named user license or an authenticated user license. The challenge here is the cost of authenticated licenses makes this solution unappealing, hence the need to try to accomplish something with just the Portal.

Does anyone have any creative solutions for applying the AD credentials to a submission?