Shepard Fairey, the artist behind former President Obama’s “Hope” campaign poster, says an imposter account is selling his work as an NFT.

On Twitter, he wrote that an unverified account with the handle @obeygiantart was auctioning off one of his pieces on the NFT marketplace Rarible (Fairey’s Twitter handle is @obeygiant).

It’s a tale as old as the internet itself—impersonator accounts have been an issue on Twitter and Facebook since the very beginning. It’s why blue-check verification systems were first developed: to tell the real accounts from the fake ones.

The Fairey imposter was likely inspired by Fairey’s actual NFT, which was released last month.

NFTs are non-fungible tokenstokens that can be used as a sort of proof of ownership for just about anything on the internet. Over the last several months, the market for NFTs in the digital art world has skyrocketed—and, in the first quarter of 2021, NFT sales in general have generated more than $1.5 billion, according to DappRadar.

Rarible is one of many NFT marketplaces that have benefited from the boom. It has a check-based verification system of its own, so if you bid on the fake Fairey NFT it’s at least partially your own fault. But the confusion points to bigger questions with the craze around NFTs and digital ownership. What makes something the authentic NFT? Is something valuable if you can just screenshot it? And what are the copyright issues involved here?

Defrauding “any member of the Rarible Community” through impersonation is explicitly forbidden in the site’s terms of service. The high bid for the fake Fairey NFT is now just over $100—it's unclear, however, if the pseudonymous bidder, “MarcoVHNFT,” knows they aren't buying an authentic Fairey NFT.

Rarible did not immediately respond to Decrypt's request for comment.