1. Setup

2. Recording

F/P allows you to record several tracks of data, simultaneously, into a single standard MP4 file that is compatible with normal media tools.

  • Video tracks -- F/P can record simultaneously from the front and rear cameras

  • Audio track -- just your standard phone microphone

  • Location track -- a stream of phone's GPS coordinates

  • Sensor track -- a stream of the phone's internal sensors (magnetometer, accelerometer, etc)

F/P uses several methods to protect against manipulating or faking these tracks. These include:

  • cryptographically signing the recording streams (eg video and audio)

    • this prevents modification of the recording, and proves that it was generated by your username

  • syncing timestamps with the F/P Server

    • this proves that the recording was taken at a specific time -- prevents anyone presenting an old recording as new!

  • embedding phone location and sensor data in the recording

  • this proves the location of the recording, and can be used to validate video and audio streams (for example, they can prove that someone didn't just take a new recording of a manipulated video being played on a high resolution screen!)

There are several other more sophisticated methods under investigation.

3. Verifying

Each F/P recording stores all the information needed for verification, including metadata, signatures, and sensor data. To verify a F/P recording, simply open it in the F/P App and click Verify (note: this requires an internet connection so that the F/P Server can be consulted for signature and timestamp validity). You can use any common file sharing method to exchange recordings -- though some systems may re-encode the recording which will destroy the F/P side-channels.

NOTE: Absolutely no personal information or any of the content of your recording is shared with the F/P Server. The only information shared and stored is:

  • your chosen username and your F/P public key -- a public cryptographic key generated for you by the F/P App. The private key is stored only on your phone.

  • Start and Stop Timestamps for each recording, as well as a cryptographic digest of the recording contents, and a cryptographic signature from the F/P App Key and from your F/P User Key.