Sony blames hacker group Anonymous for latest attack

"The data breach involving Sony's PlayStation Network has the potential to become the 'Great Brink's Robbery' of cyber attacks," Bono Mack said. "And the 'take' keeps going up."

Mack called the refusals to testify by both Sony and the email-marketing firm Epsilon, which also recently experienced a massive data breach, "unacceptable."

"What about the millions of American consumers who are still twisting in the wind because of these breaches? They deserve some straight answers, and I am determined to get them," Bono Mack said.

Several lawmakers criticized Sony for taking almost a week before notifying consumers, but in his letter Hirai said Sony notified authorities as soon as it was certain of the breach and had to make sure its system was secure before going public.

"I am of course aware of the criticism Sony has received for the time taken to disclose information to our customers," Hirai wrote.

"I hope you can appreciate the extraordinary nature of the events the company was facing — brought on by a criminal hacker whose activity was neither immediately nor easily ascertainable."

The hearing featured witnesses from the Secret Service and Federal Trade Commission along with privacy advocates, all of whom agreed when asked that the industry's current efforts with respect to data security are insufficient.

Bono Mack said she plans to reintroduce an updated version of her data privacy bill but declined to specify a timeline. All four witnesses said Congress should pass comprehensive data security legislation that would pre-empt the current patchwork system of individual state laws.