Blockchains are no longer as immutable as previously believed, which might give Wall Street second thoughts in its adoption.

When hackers exploited loopholes they found in the Distributed Autonomous Organization’s smart contracts, they stole approximately 3.6 million ether tokens (ETH) worth tens of millions of dollars.

As a result, Ethereum Project released a ‘hard fork’ for the Ethereum blockchain, which for intents and purposes dialed back the blockchain to the pre-hack status and tarnished the technology’s reputation of immutability.

“The hard fork certainly has highlighted some issues around the blockchain that the industry needs to think about or has not thought about seriously enough,” said Richard Johnson, senior analyst, market structure and technology at industry research firm Greenwich Associates.

Maybe there should be a mechanism to roll back changes made to a blockchain, he suggested. “When someone steals a digital asset, there is no outside mechanism to cancel that transaction or render what was stolen useless.”

A privately operated blockchain, the most likely type to be used in the financial markets, might have more security around it, but it still could be compromised by a bad actor in a similar way that bad actors hacked the SWIFT messaging network, noted Johnson.

“The vulnerabilities are less on a private network, but there is still potential there,” he said.

Johnson also noted that the DAO hack involved exploiting the smart contract that powered the DAO, not the ethereum blockchain on which the DAO operated.

If companies plan to use smart contracts that have the potential of moving around significant sums of money, they should have better safeguards in place than were in place for the DAO, he suggested.

Another lesson Wall Street should take away from the DAO failure is that changes to a blockchain could have long-term consequences.

Before the Ethereum Project implemented its hard fork of its code, it polled the Ethereum community to see how many people wanted to fork the Ethereum code. Close to 85% wanted to adopt the new code while 15% wanted to remain using the unaltered Ethereum code.

After the Ethereum Project rolled out its fork, approximately 15% of the Ethereum community decided to remain using the original code, now dubbed ‘ethereum classic’ (ETC).

The new currency has the sixth largest market capitalization ($1.75 million) among electronic currencies compared to ethereum’s approximate $996 million market capitalization.

Alex Sunnarborg, founder and CFO of digital currency research firm Lawnmower, does not expect ethereum classic to be around for the long term.

“Some exchanges have added trading support for ethereum classic, which means that we might see some trading volume,” he said. “I tend to think that it will slowly fade away.”

For more on Blockchain:

• Baby Steps for Smart Contract Standards
• How the Tech Behind Bitcoin Could Revolutionize Wall Street
• Unmasking Bitcoin Identities: The Next Level of Thwarting Illicit Activity on the Blockchain Has Aarrived