Having access to RSA's internal networks and the SecurID source code might give criminals some subtle way of attacking SecurID users, but it shouldn't give them a way of completely breaking RSA's encryption, said Thorsten Holz, an assistant professor at Ruhr-University Bochum who studies computer security. "If RSA implemented everything correctly, nobody should be worried too much," he said.

However, from RSA's statement, it's not clear exactly what the hackers were able to learn off the company network.

According to Nate Lawson, a cryptographer and the founder of Root Labs, there's simply not enough information available to tell how bad the problem really is. "If I was a customer of theirs it makes it really hard to know what I need to do. They recommend a lot of things that people are already doing," he said.

RSA representatives did not immediately return calls and e-mails seeking comment.

No EMC products were affected by the attack and RSA doesn't think other RSA products are affected. Also, there's no evidence that customer or employee information was compromised, Coviello said.