In the largely mysterious world of digital currency trading, a Delray Beach-based exchange is at the center of a nationwide class action lawsuit filed by traders accusing its chief executive of absconding with about $5 million.

Project Investors Inc., which does business as Cryptsy, and CEO Paul Vernon of Boynton Beach are accused of defrauding investors. They’re defendants in a four-count suit brought by class representative Jinyao Liu of Virginia alleging negligence, unjust enrichment, conversion and violation of Florida’s Deceptive and Unfair Trade Practices Act.