Google recently announced Eddystone -- open source beacons that will provide some competition for Apple's iBeacon.
The bluetooth beacon platform is both open source and cross platform, which means the small battery-powered devices will be compatible with iOS, Android and other devices. The bluetooth low energy (BLE) beacons can trigger actions when a smartphone or tablet device similar to other beacons, similar to the technology that is already in use by many retailers.
However, instead of broadcasting a unique message publicly, Google announced Eddystone has a way of communicating privately to particular individuals. Ephemeral Identifiers (EIDs) enables beacons to send a signal that only "authorized clients" can identify. A possible application of EIDs is secure luggage identification or finding lost keys.