By Erika Icon

YNOT – Don’t be too quick to get rid of your external back-up drives. “Cloud” storage may not be as safe — or as private — as it seems.

Cloud storage, essentially shared virtual storage space on a remote server with built-in redundancy, is popular because in most cases it’s cost-effective, easy to use, reasonably secure and relatively private. Moreover, material stored “in the cloud” usually can be accessed anywhere, anytime, on any device, and sharing is as easy as providing a secure link to trusted compatriots.

Of late, though, users are beginning to see a darker side to popular cloud services like Dropbox, Google Drive, Microsoft SkyDrive and Amazon Cloud Drive. Some have found legal copies of DVDs deleted without warning, on the provider’s assumption the material was pirated. Others have reported porn filters rejecting summer-vacations pictures as pornography.

Many of the popular cloud storage providers perform routine sweeps of customers’ files. According to NBC News, the focus of the sweeps is child abuse imagery, but according to most terms of service, anything a cloud provider deems objectionable is fair game for deletion — and reporting to legal authorities.

“When users place their data with cloud computing services, they lose the ability to maintain complete control of that information,” Electronic Privacy Information Center Associate Director Lillie Coney told NBC.

Recently, a Maryland man was charged with possession of child pornography based on 23 images Verizon Online found during a sweep of his cloud drive. By law, storage providers must report “known or suspected instances of child pornography.”

Some services routinely police storage, and others do not. Apple, Microsoft and Verizon Online specifically warn users they reserve the right to screen stored files at any time for any reason. Third-party vendors usually do the filtering.

Microsoft is particularly vigilant, employing a system developed in conjunction with Dartmouth College to scan uploads for characteristics of 16,000 known child-porn images. All content stored on Microsoft’s servers is screened twice: when it arrives and when it departs.

Dropbox, Amazon and Google investigate only if they suspect illegal activity.

“There is a need to update [electronic privacy legislation] to help establish the boundaries for due process, police authority and the role of the courts,” Coney said. “If too many decisions are left to individual vendors or cloud service providers, that may bring more harm than good.

“Terms of service should not be the standard for due process,” she continued. “Laws enforced by the courts should establish what is permissible and what is not. The increased use of cloud computing services will raise questions regarding Fourth Amendment protections for that information, property rights between content creators and content holders, and the ability to port data from one cloud service to another.”

Adult cloud storage provider Pink Visual has bumped into the issue on occasion with its PVLocker service. PVLocker users are allowed to store not only content they purchase through the service, but also material they purchase elsewhere. Like mainstream clouds, PVLocker provides password-protected, secure storage. Unlike most mainstream clouds, PVLocker does not allow users to share their content with others. According to a spokesman, that rule is designed to minimize the potential for content piracy.

Pink Visual Communications Director Quentin Boyer said PVLocker guarantees users’ stored content won’t be scanned or deleted unless the service detects unauthorized sharing, or receives a complaint from a content owner or an official request from law enforcement.

“Naturally, if we do have reason to believe that any user’s uploaded content is illegal, we will take the appropriate action — like removing files in response to takedown notices — but since we don’t permit file-sharing or link-sharing through our system, we haven’t had a problem with that sort of thing thus far,” Boyer said. “And we don’t anticipate that it will become a problem for us.

“The bottom line is this: If you want legitimate private storage and backup, PVLocker is a great solution, but if you want to share your files, PVLocker is simply not the place for you,” he added. “We will catch that activity, and we will shut it down.”

Even if everything in your cloud is kosher, Boyer and others recommend backing up essential items on secure, long-term, locally held media like external hard drives just to be safe. Cloud storage is primarily for convenience, not for posterity.