Facebook Inc (FB.O), facing growing skepticism about its digital currency project Libra, on Sunday said the initiative could use cryptocurrencies based on national currencies such as the dollar, instead of the synthetic one it initially proposed. David Marcus, who heads the Libra project for Facebook, told a banking seminar the group’s main goal remained to create a more efficient payments system, but it was open to looking at alternative approaches for the currency token it would use. “We could do it differently,” he said. “Instead of having a synthetic unit ... we could have a series of stablecoins, a dollar ... (full story)