Those responsible for the recent 51% attack on Ethereum Classic (ETC) have reportedly returned $100,000 worth of stolen funds to an affected cryptocurrency exchange,, after the firm tried to contact the attacker.

According to a recently published post hadn’t heard back from the attackers until now. Since some of the stolen funds were returned, the exchange now believes the hacker may have been a white hat hacker, and not someone trying to profit off of the move.

We still don't know the reason. If the attacker didn't run it for profit, he might be a white hacker who wanted to remind people the risks in blockchain consensus and hashing power security noted, however, that its analysis found ETC’s blockchain is still vulnerable to attacks and, as such, has raised the number of confirmations on its platform to 4,000. It has also launched a “strict 51% detect for enhanced protection.”

It advised other crypto exchanges to adopt similar measures to protect themselves against similar attacks in the future. As CryptoGlobe covered, the exchange revealed earlier that it was affected by the 51% attack on Ethereum Classic, as it had to cover nearly $200,000 worth of losses after 40,000 ETC tokens were taken from its wallets.

While initially the development team behind ETC claimed the 51% appeared to not be an actual attack, it soon recognized it was. A private ETC mining pool has recently been found to be accumulating hashpower since the attack, which could mean it’s planning to do the same thing.

Meanwhile Grayscale Investments, the organization behind the Ethereum Classic Investment Trust (ETCG), informed some of the investors that contacted them about the incident that ETCG’s funds are “not at direct risk.”

This, as according to Vertcoin developer Gert-Jaap Glasergen, 51% attacks can only double spend the attacker’s own coins, not someone else’s. The risk, as such, is for those who accept ETC – or another attacked cryptocurrency – for goods and services, like cryptocurrency exchanges.

At press time, ETC is trading at about $4.55 after falling 2.3% in the last 24-hour period. After the attack, the cryptocurrency’s price dropped from about $5 to a $4.3 low.