LONDON (AP) — As investors and investigators weigh the damage of Yahoo's massive breach to the internet icon, information security experts worry that the record-breaking haul of password data could be used to open locks up and down the web. While it's unknown to what extent the stolen data has been or will be circulating, giant breaches can send ripples of insecurity across the internet. "Data breaches on the scale of Yahoo are the security equivalent of ecological disasters," said Matt Blaze, a security researcher who directs the Distributed Systems Lab at the University of Pennsylvania, in a message posted to Twitter . A big worry is a cybercriminal technique known as "credential stuffing," which works by throwing leaked username and password combinations at a series of websites in an effort to break in, a bit like a thief finding a ring of keys in an apartment lobby and trying them, one after the other, in every door in the building.Read more on NewsOK.com