NSA whistleblower Edward Snowden has warned against the use of cloud storage service provider Dropbox, accusing the company of being "hostile to privacy" and a "wannabe" collaborator in the US government's PRISM snooping programme.
Snowden, the former National Security Agency intelligence analyst who revealed the extent of government surveillance on citizens, made the comments in an interview with The Guardian in Moscow, where he's currently living under asylum.
Snowden described Dropbox as a "wannabe PRISM partner", suggesting that the cloud storage company's appointment of former US Secretary of State Condoleezza Rice - who the whistleblower described as "probably the most anti-privacy official you can imagine" - to its board in April flies in the face of privacy rights.
"She's one of the ones who oversaw Stellar Wind and thought it was a great idea," Snowden continued, referencing the codename for the warrantless collection of data which began under the George W. Bush administration, adding that it means that Dropbox is "very hostile to privacy".
Snowden argued that cloud storage providers should follow a zero knowledge model of business, where they store and host files uploaded by customers, but don't have access to the information stored within their service.
"By depriving themselves of the ability to read the information, of the ability to sort-of analyse and manipulate the information without the customers' consent or authorisation, that's the only way they can prove to the customers that they can be trusted with their information," he said.
Snowden recommended that anyone who doesn't want governments having the ability to access their files should use SpiderOak, a ‘zero-knowledge' cloud storage service where the server doesn't know what information is stored within it.
That means it's never at risk of being hacked or compromised by those who aren't supposed to see it and only the uploader of the information, with the use of a unique and long login key, can see the data.
"SpiderOak has structured their system in such a way you can store all of your information on them with the same sort of features that Dropbox does, but they literally have no access to the content," said Snowden.
"So while they can be compelled to turn it over, the law enforcement agencies still have to go to a judge and get a warrant to actually get your encryption key from you," he added.
Since Snowden's remarks have become public, Spideroak has said that it has recevied a much higher signup rate than usual.
However, in an emailed statement, Dropbox rejected Snowden's privacy concerns about its service, claimed that "safeguarding our users' information is a top priority at Dropbox".