The lack of a clear explanation has led to a lot of chatter among security experts.

"The RSA situation has been going on for a couple months now, with no shortage of rumors swirling about what was lost, and no real guidance from RSA on the risk to their customers (at least none outside of NDA)," wrote Dan Kaminsky, an independent security researcher, in a

The confusion has caused some perception problems for RSA about its products, said the chief security officer at one company who spoke on condition of anonymity because he didn't want to jeopardize his company's relationship with RSA's parent company, EMC. "As a buyer right now, their name is just something I'd stay away from," he said. "Do you want to tie your reputation to them and not know enough?"

RSA said it can't say any more about what was taken, or by whom, for "security reasons." People familiar with the situation said disclosing exactly what data was taken could potentially harm the reputation of some RSA customers, which is something RSA is taking pains to avoid.

Christopher Ipsen, chief information security officer for the State of Nevada, said his organization plans to take RSA up on its offer to reissue SecurID tokens. But he said he understands why RSA might be reluctant to release details of the attack. "You don't want to give too much information out about the exploit," he said. "But there is an appropriate time when full disclosure is imperative."