A method of operating a computing device, the method comprising: a control application running on the computing device storing data on the computing device in an encrypted form; a data access application running on the computing device, receiving a request to access the data using the data access application; determining whether the data access application has available a shared encryption key that is available to the control application; if the data access application does have available the shared encryption key, using the shared encryption key to encrypt the request for access to the data and sending the encrypted request from the data access application to the control application, and if the data access application does not have available the shared encryption key, negotiating the shared encryption key with the control application, using the negotiated shared encryption key to encrypt the request for access to the data and sending the encrypted request from the data access application to the control application; and the control application receiving the encrypted request, decrypting the encrypted request using the shared encryption key, and making the data stored on the computing device in encrypted form available to the data access application in response to the decrypted request, wherein making the data stored on the computing device in encrypted form available to the data access application comprises: the control application providing a data access application key to the data access application once the control application has authenticated a user of the computing device, the transmission of the access application key to the data access application being encrypted with the shared encryption key; and the data access application decrypting the stored data by using the data access application key to decrypt a key that was used to encrypt the stored data. a control application running on the computing device storing data on the computing device in an encrypted form; a data access application running on the computing device, receiving a request to access the data using the data access application; determining whether the data access application has available a shared encryption key that is available to the control application; if the data access application does have available the shared encryption key, using the shared encryption key to encrypt the request for access to the data and sending the encrypted request from the data access application to the control application, and if the data access application does not have available the shared encryption key, negotiating the shared encryption key with the control application, using the negotiated shared encryption key to encrypt the request for access to the data and sending the encrypted request from the data access application to the control application; and the control application receiving the encrypted request, decrypting the encrypted request using the shared encryption key, and making the data stored on the computing device in encrypted form available to the data access application in response to the decrypted request, wherein making the data stored on the computing device in encrypted form available to the data access application comprises: the control application providing a data access application key to the data access application once the control application has authenticated a user of the computing device, the transmission of the access application key to the data access application being encrypted with the shared encryption key; and the data access application decrypting the stored data by using the data access application key to decrypt a key that was used to encrypt the stored data. the control application providing a data access application key to the data access application once the control application has authenticated a user of the computing device, the transmission of the access application key to the data access application being encrypted with the shared encryption key; and the data access application decrypting the stored data by using the data access application key to decrypt a key that was used to encrypt the stored data.