Alleged usernames and passwords for online document-sharing site Dropbox were published on Monday on Pastebin website, although Dropbox asyes the data was not associated with its users' accounts. The anonymous user, who claims to have hacked close to 7 million accounts, is calling for Bitcoin donations to fund the operation.

"We will keep releasing more to the public as donations come in, show your support," the anonymous Pastebin user said on the site.

"The usernames and passwords referenced in these articles were stolen from unrelated services, not Dropbox. Attackers then used these stolen credentials to try to log in to sites across the internet, including Dropbox. We have measures in place to detect suspicious login activity and we automatically reset passwords when it happens," Dropbox said on Monday. The company on Tuesday provided further feedback: "The list of usernames and passwords that have been posted online are not associated with Dropbox accounts."

Edward Snowden last week advised those concerned about their privacy to "get rid of Dropbox" and cease using Facebook and Google.