President Barack Obama ceremoniously signed an executive order on Friday that calls for private companies to work together when it comes to cyberthreats and more readily share that information with the government. Yet the leaders of the nation's most powerful tech giants (with the exception of Apple) were noticeably absent from the event. That means CEOs from Google, Facebook, Yahoo and Microsoft were nowhere to be seen. They had declined invitations to the summit. SEE ALSO: 11 free tools to protect your online activity from surveillance The absences are, in a sense, a form of protest. Much of Obama's speech at Stanford University proclaimed the importance of data security, but friction has developed between the Obama administration and the nation's tech giants on the heels of the NSA spying scandal. Larry Page (Google), Eric Schmidt (Google), Mark Zuckerberg (Facebook), Marissa Mayer (Yahoo) and Satya Nadella (Microsoft) are part of a group of very powerful companies that have publicly campaigned for the reform of government surveillance. When whistleblower Edward Snowden leaked top secret documents and information to journalists, a sophisticated mass surveillance of U.S. citizens' data was exposed. That included breaking into the email systems of companies like Google, Microsoft and Yahoo — something those companies, of course, did not take lightly. Since then, extra steps havebeen taken to regain users' trust. For example, Facebook added Tor capabilities, the software and browser that aims to help people browse the web anonymously. But Apple CEO Tim Cook was there, and took the chance to reveal that Apple Pay was embarking on a partnership with the federal government so its paperless payment system could be used for transactions such as entry into national parks. Apple Pay support will also be added to Social Security and veterans' benefits cards. Still, Apple has repeatedly protested the government's actions; Cook himself commented on the importance of privacy at the event on Friday. "Our customers' trust means everything to us," he said. "Privacy and security are built into every one of our products and services from their inception." Have something to add to this story? Share it in the comments.