The announcement comes after Apple unveiled a similar plan for its iPhones and iPads, and amid heightened concerns about privacy of personal technology.

A Google spokesman said encryption is already offered for the Android system used on smartphones and tablets, but that this will be turned on automatically in the upcoming version of Android.

"For over three years Android has offered encryption, and keys are not stored off of the device, so they cannot be shared with law enforcement," the spokesman said in a statement.

"As part of our next Android release, encryption will be enabled by default out of the box, so you won't even have to think about turning it on."

Google has not said when the next update of Android will be released. Apple announced late Wednesday that its new encryption will be built into the iOS 8 operating system available on the iPhone 6, which goes on sale Friday. It also can be installed on many existing iPhones and iPads.

"Your personal data such as photos, messages (including attachments), email, contacts, call history, iTunes content, notes, and reminders, is placed under the protection of your passcode," says the new policy on Apple's website.

"Unlike our competitors, Apple cannot bypass your passcode and therefore cannot access this data. So it's not technically feasible for us to respond to government warrants for the extraction of this data from devices in their possession running iOS 8."

The updates come in the wake of revelations of massive government surveillance programs that sweep up data from computers and other devices.

Leaked documents from former National Security Agency contractor Edward Snowden have highlighted concerns about the role of major tech firms in these programs.