Edward Snowden, the former National Security Agency contractor who blew the whistle on the secret surveillance activities being carried out by the federal government, is warning accountants and other professionals to be concerned about the privacy of their communications.

In an interview with The Guardian, Snowden described how phone and email communications are vulnerable to tracking and what professionals such as journalists need to do to protect themselves.

“The work of journalism has become immeasurably harder than it has ever been in the past,” he said. “Journalists have to be particularly conscious about any sort of network signaling, any sort of connection, any sort of license plate reading device that they pass on their way to a meeting point, any place they use their credit card, any place they take their phone, any email contact they have with a source, because that very first contact before encrypted communications are established is enough to give it all away.”

He was asked by Guardian reporters Alan Rusbridger and Ewen MacAskill about what other professionals besides journalists should be changing their behavior as a result of what is now known about the surveillance, and he listed accountants among them.

“It’s a constantly increasing list, one that we’re not even aware of today,” Snowden replied. “I would say lawyers, doctors, investigators, possibly even accountants, anyone who has an obligation to protect the privacy interests of their clients is facing a new and challenging world, and we need new professional training and new professional standards to make sure that we have mechanisms to ensure that the average member of our society can have a reasonable measure of faith in the skills of all of the members of these professions.”

Asked about whether technology is compatible with privacy, Snowden replied, “Absolutely, technology can actually increase privacy, but not if we sleepwalk into new applications of it without considering the implications of these new technologies. The question is, why are our private details that are transmitted online, why are our private details that are stored on our personal devices any different than the details and the private records of our lives that are stored in our private journals? There shouldn’t be this distinction between digital information and printed information, but the government in the United States and the government in the United Kingdom and many other countries around the world is increasingly seeking to make that distinction because they recognize that it vastly increases their powers of investigation.”