As users start carrying multiple mobile devices, we
		  propose a novel, token based mobile device unlocking
		  approach. Mobile devices are conjointly shaken to transfer
		  the authentication state from an unlocked token device to
		  another device to unlock it. A common use case features a
		  wrist watch as token device, which remains unlocked as long
		  as it is strapped to the user’s wrist, and a locked mobile
		  phone, which is unlocked if both devices are shaken
		  conjointly. Shaking can be done single-handedly, requires
		  little user attention (users don’t have to look at the
		  device for unlocking it) and does not cause additional
		  cognitive load on users. In case attackers gain control
		  over the locked phone, forging shaking is difficult, which
		  impedes malicious unlocks. We evaluate our approach using
		  acceleration records from our 29 people sized ShakeUnlock
		  database and discuss influence of its constituent parts on
		  the system performance. We further present a performance
		  study using an Android implementation and live data, which
		  shows the true negative rate of observational attacks to be
		  in the range of 0.8 – if an attacker manages to gain
		  control over the locked device and shake it in parallel to
		  the device owner shaking the token device.<br>
<br><pre>@article{Findling_17_ShakeUnlockSecurelyTransfer,
  author = {Findling, Rainhard Dieter and Muaaz, Muhammad and Hintze, Daniel and Mayrhofer, Ren\'e},
  title = {ShakeUnlock: Securely Transfer Authentication States
  		  Between Mobile Devices},
  journal = { {IEEE} Transactions on Mobile Computing ({TMC})},
  year = {2017},
  volume = {16},
  number = {4},
  pages = {1163--1175},
  month = apr,
  doi = {10.1109/TMC.2016.2582489},
  keywords = {Mobile environments, Security and Privacy Protection,
  		  Authentication, Time series analysis},
  url = {https://ieeexplore.ieee.org/document/7494938/}
}
</pre>