Ephemeral key storage

Abstract

A portable communications device is adapted with a controlled self-erasing option to programmably store user content and key data based on a desired limited lifespan for such data. This allows for improved security in the event the device is misplaced or lost as the onboard user data eventually becomes physically destroyed and unreadable to a third party without requiring a remote access destruction capability.

What is claimed is: 
     
         1 . A self-erasing data storage device with controllable data retention capabilities comprising:
 a non-volatile memory (NVM) including an ephemeral memory portion adapted to store first programmed user key data, including at least a first user key for accessing a first user data file;   a controller circuit for implementing a user selectable slow self-erase mode for said first programmed user key data on the ephemeral memory portion when enabled by a user of the data storage device;   wherein said user selectable slow self-erase mode enables a slow self-erase operation which can be imposed continuously on key data elements storing said first programmed user key data to remove charge;   wherein the controller circuit is adapted to effectuate a controllable limited data retention memory for said first user key when said selectable self-erase mode is enabled such that said key data elements are set to an erased state within a predefined time period.   
     
     
         2 . The device of  claim 1 , wherein said slow self-erase operation is implemented solely through a leaky gate structure for said key data elements. 
     
     
         3 . The device of  claim 2 , wherein said slow self-erase operation is implemented during periods when said key data elements are unbiased. 
     
     
         4 . The device of  claim 2  further including a self-erase bias circuit configured to assist in actively erasing said data storage elements by slowly draining charge. 
     
     
         5 . The device of  claim 1  wherein said slow self-erase operation is implemented exclusively by a self-erase bias circuit configured to actively erase said data storage elements by slowly draining charge. 
     
     
         6 . The device of  claim 1 , wherein said self-erase mode includes user selectable options defining a trigger event and/or an onset time for said self-erase. 
     
     
         7 . The device of  claim 1  wherein said first user key includes a public key and/or a private key. 
     
     
         8 . The device of  claim 1 , wherein said self-erase mode includes user selectable options specifying and controlling said predefined time period. 
     
     
         9 . The device of  claim 1  wherein the ephemeral portion of the NVM also stores user data to impart a limited retention period for such data. 
     
     
         10 . The device of  claim 1 , further including a communications port for wirelessly transmitting said user key data and/or other data from said ephemeral memory portion of said NVM. 
     
     
         11 . The device of  claim 10 , wherein the controller selectively transmits data from said ephemeral memory portion to an external storage device in response to detecting one or more of a wireless network, a predetermined event, an expiration of a predetermined time interval and/or presence in or departure from a predetermined location. 
     
     
         12 . The device of  claim 1 , further including a universal serial bus (USB) port for exchanging data with a smartphone and/or other computing device. 
     
     
         13 . The device of  claim 1 , further including a refresh circuit enabled by said user selectable options and configured to refresh said data storage elements when said storage device is powered. 
     
     
         14 . The device of  claim 1 , wherein said self-erase mode includes user selectable options to disable said self-erase mode when said storage device is powered. 
     
     
         15 . The device of  claim 1 , wherein said controller circuit issues periodic alerts indicating a remaining lifetime of said user key data. 
     
     
         16 . The device of  claim 1 , wherein said user key data can be completely physically erased without connecting the device to a power source, and without requiring a remote self-destruct operation. 
     
     
         17 . The device of  claim 1 , wherein said device is incorporated within a vehicle sensor recording system. 
     
     
         18 . The device of  claim 1 , wherein the predetermined time period for the self-erase exceeds 1 hour. 
     
     
         19 . A portable self-erasing data storage device with controllable data retention capabilities comprising:
 a non-volatile memory (NVM) including an ephemeral memory portion adapted to store user key data, including at least a first user key for accessing a first user data file stored on the storage device;   said ephemeral memory portion having data storage elements adapted with a charge storage structure including a leaky data storage gate that self-erases after being set to a first logical programmed state by losing charge during periods in which said elements are in an unbiased quiescent state;   a controller circuit for implementing a user selectable self-erase mode for said user key data on the NVM when enabled by a user of the data storage device, which self-erase mode includes a user selectable target erase period;   wherein when said selectable self-erase mode is enabled the controller circuit effectuates a controllable limited data retention memory for said first user key such that data storage elements associated with said user key data transition to a second logical erased state within said user selectable target erase period.