I thought of an alternative currency that many would accept. Bills made from paper but with strips of silver all in lamination. It's the silver that gives the bill value. This would work great for small denominations but if you wanted larger gold could be used instead. Given modern tech a spectral analysis could be used to confirm legitimacy so counterfits wouldn't be an issue. Simply containing a precious metal would be enough in most people's eyes and they'd be easy to produce.