Google this week announced general availability of an option that lets customers of its cloud services use their own keys for encrypting sensitive data stored online.
Google first introduced its Customer-Supplied Encryption Keys (CSEK) for Compute Engine in beta form last year. The feature basically enables enterprises to protect their data using encryption keys that are not owned or managed by Google. The company claims it will only require and hold customer keys temporarily to fulfill requests such as starting a virtual machine or attaching a disk.
"With CSEK, disks at rest are protected with your own key that cannot be accessed by anyone, inside or outside of Google, unless they present your key," Google product managers Maya Kaczorowski and Eric Bahna wrote on the company's Cloud Platform Blog.
Currently, Google's cloud platform encrypts all customer data stored on its servers by default, without the customer having to do anything to initiate the process.
When an enterprise supplies its own encryption key, Google will use that key to protect the Google-generated keys used to encrypt and decrypt the data, according to an official description of how CSEK works. Any key the customer provides must be 256-bit string encoded in the RFC 4648 standard, according to Google.
Customer-supplied keys never will be stored on Google's servers, effectively ensuring Google cannot access the protected data. "This also means that if you forget or lose your key, there is no way for Google to recover the key or to recover any data encrypted with the lost key," the company warned.
Key management is a big issue for organizations looking to move sensitive data to the cloud. Although many cloud vendors encrypt customer data at rest these days, the fact that they also hold the decryption keys has proved to be an issue for many organizations, especially following Edward Snowden's leaks about U.S. government access to cloud-hosted data.
Customer-supplied encryption keys eliminate that problem by giving enterprises more direct control over their data in the cloud. But it also can raise separate issues for enterprises pertaining to key management.
By announcing general availability of CSEK this week, Google has joined a growing number of cloud service providers who give enterprises the option of bringing their own keys for protecting cloud-hosted data. Some, such as Amazon, have been giving customers the option for quite some time, while others, such as Box with its Full Encryption Key Control service, have made the feature available to customers relatively more recently.
Like Google's CSEK, Box gives its customers exclusive key control and offers what it describes as an unchangeable audit log for recording all key usage that Box can never change or tamper with.
CSEK is currently available in the United States and seven other countries including Canada, Denmark, France, Germany and the UK. It is scheduled to be rolled out to Australia, Norway, Mexico and Italy later this month.