A new way to encrypt photos on the cloud

A new model by researchers at Columbia Engineering can encrypt photos uploaded to cloud services including Google Photos and iCloud without making any change to the services.

Encrypting a photo of a sunflower (upper left) using Columbia Engineering researchers' Easy Secure Photos system results in three image files that contain data about the original photo's red (upper right), green (lower left), and blue (lower right) information.

Encrypting photos on the cloud is a difficult task as most cloud services are not compatible with existing encrypting techniques. For example, Google Photos compresses uploaded files to reduce their sizes, but in the process, it would corrupt encrypted images.

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Now, a team of researchers at Columbia Engineering have developed a new technique to encrypt photos on popular cloud-based storage services, including Google Photos, Apple and Flickr. Their method requires no change to be made to the services.

Called Easy Secure Photos (ESP), the technique encrypts photos uploaded to the cloud service, making it difficult for both hackers and cloud service providers to decipher. It employs an image encryption algorithm whose resulting files can be compressed and still get recognised as images, albeit ones that look like black and white static to anyone except authorised users.

The model will also work for lossy and lossless image formats such as JPEG and PNG, and is perfectly compatible with smartphone apps, the team said in a study titled ‘Encrypted Cloud Photo Storage Using Google Photos’.

Encrypting each image results in three black-and-white files with each one encoding details about the original image’s red, green or blue data. The model will also create and upload encrypted thumbnail images to cloud photo services. Authorised users can browse thumbnail galleries using image browsers that incorporate the same model, the team noted.

The model will also enable multi-device access, which requires a single key or code to encrypt and decrypt the image. The ESP model will make it easy for the user to verify authenticity in multiple devices using the ESP-enabled app without having to remember the key.

“Our system adds an extra layer of protection beyond your password-based account security,” said one researcher. “The goal is to make it so that only your devices can see your sensitive photos, and no one else unless you specifically share it with them.”