The U.S. currency of the future might have hidden, machine-readable technology embedded right into the bills.

In an effort to prevent counterfeiting, the Treasury Department Bureau of Engraving and Printing put out a request for information seeking never-before-seen ideas for weaving technology into bills that could then be read by special machines, verifying the bill’s authenticity.

The solution can either “be incorporated into the banknote or applied to the note,” but must meet four requirements:

Difficult to discover on a banknote even by subject matter experts.

Difficult to explain the functionality or detection mechanism of the feature.

Readable by a highly discriminating standalone detection system.

Resistant to simulation or duplication, both in terms of material and response.

The request gives little guidance on the sort of technologies that Treasury is looking for, such as masked barcodes, RFID or other embeddable IT. However, proposed solutions must be “novel and not commercially available” but also must be lab tested, with prototypes available for Treasury officials to evaluate.

“Technologies and/or materials submitted for consideration will be reviewed for inherent and relative effectiveness as a security feature, and may be further assessed for compatibility with design and production factors, durability, environmental acceptability and other processing requirements,” the RFI states.

Vendors with an idea to pitch can send their prototypes and a technical description of the product to the bureau for an initial screening.

The RFI also does not disclose how ubiquitous the detecting machines will be—e.g., if clerks at the corner store will use them like counterfeit detector pens—or whether all denominations will have the technology.

But there doesn’t seem to be much rush on Treasury’s part: The response deadline for the RFI is 2 p.m. Jan. 24, 2020.