The November hacking of Sony Pictures Entertainment was "one of the most vicious and malicious cyberattacks" in recent history, Sony CEO Kazuo Hirai said Monday during his keynote address at the annual Consumer Electronics Show in Las Vegas.
"I am very proud of all employees and all the partners we've worked with as well who stood up against the extortionate effort of these criminals," he added.
Monday marked the first time that Hirai publicly addressed the recent hack, which included the release of embarrassing private emails between Sony Pictures chair Amy Pascal and producer Scott Rudin.
It also led to the cancellation of the theatrical release of James Franco and Seth Rogen's The Interview, a Sony comedy about a plot to assassinate North Korean leader Kim Jong Un. It was later made available in limited release and online.
U.S. officials blamed North Korea for the attack, after the North Korean government declared the film an "act of war" last June.
In his address, Hirai emphasized Sony's commitment to free speech.
"I have to say freedom of speech, freedom of expression, freedom of association, are important lifelines of Sony and our entertainment business," he said.
Hirai praised the work of employees "who stood up against the criminals' efforts and worked 24 hours a day to bring The Interview to audiences in the United States and Canada, online and in motion picture theaters."
Last week, President Barack Obama imposed stricter sanctions against North Korea, calling the cyberattack "provocative, destabilizing and repressive."