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.