Speaking on a Unitize digital conference panel about proof-of-work, or PoW, attacks, James Lovejoy of MIT's Digital Currency Initiative, or DCI, said 51% attacks might not be evident, despite blockchain's public nature. 

Blockchains do not always show 51% attacks at first glance, Lovejoy explained on the July 9 panel. "You need an active observer to be monitoring the network to check whether or not an attack occurs," he said. 

Lovejoy has a blockchain reorganization tracker

For his DCI master's thesis, Lovejoy spun up a blockchain reorganization tracker, or reorg tracker, that examines 51% attacks, he detailed on the panel. 

The expert explained recent research shows 51% attacks as more plausible than once thought. He described the viability of such reorganizations across assets in the crypto space, given those assets' various hash rates, the costs associated with attacks, and other factors.   

Victims take the first hit of an attack

By the time the market discovers foul play on a blockchain without a tracker, people may already have suffered effects. "Up until now we've been reliant on victims to tell us about whether they've been attacked," Lovejoy said. 

"As you can imagine, if this results in insolvency or a loss of user funds, victims are often not super interested in revealing when an attack has taken place," he added. Lovejoy also detailed a plethora of other pertinent information and findings during the panel.

Multiple 51% attacks have surfaced in recent years, plaguing projects such as Ethereum ClassicandBitcoin Gold, showing such nefarious behavior as far from impossible.