The UriIO Ephemeral URL service allows you to shorten any URL so that it can be advertised by an Eddystone-URL BLE beacon.
Assuming the advertised URL is often changed during advertising, every redirect to the target destination contains a non-spoofable proof-of-proximity and timestamp, integrated in the URL in an encrypted format.
Jan. 23 2017 - the current v1 API is no longer documented or accesible via a web interface. Please use the Beacon Toy app to use the shortener.
New and improved API in progress.
Android library to advertise as a beacon, as used by Beacon Toy
Physical Web main page
Eddystone format specifications for Bluetooth Low Enery beacon