Poly Network’s hacker returns all of the stolen funds but nearly half of them are locked.

Nearly all of the $600 million stolen in what is considered one of the biggest cryptocurrency heists ever has now been returned by hackers. Poly Network, the crypto platform targeted in the attack, said Thursday that all of the funds bar $33 million worth of the digital coin tether had been transferred.

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— Poly Network (@PolyNetwork2) August 12, 2021

The hacker said they were “ready to return” the funds.

The issuer of tether, a so-called stablecoin pegged to the U.S. dollar, used a built-in failsafe to freeze the assets soon after the theft. In an unusual turn of events Wednesday, an anonymous person claiming to be the hacker said they were “ready to return” the funds. The identity of the hacker, or hackers, is not yet known. Poly Network had requested they send the money to three digital currency wallets. And, sure enough, the hacker had returned more than $342 million of the funds to those wallets by Thursday. 

The key to $268 million of assets is with Poly Network and hackers.

While almost all of the stolen funds have been sent back to decentralized network, the last $268 million of coins is currently locked in an account that requires passwords from both Poly Network and the hacker to gain access. “It’s likely that keys held by both Poly Network and the hacker would be required to move the funds — so the hacker could still make these funds inaccessible if they chose to,” Tom Robinson, the chief scientist of blockchain analytics firm Elliptic, said in a blogpost Friday. Earlier, Poly Network had asked the hacker to return funds back and offered $500,000 for exposing the vulnerability in the network.