Patent ID: 8751804

Claim:
A method of controlling access to a file, of controlling access to a file, the method comprising: creating a file encryption key based on (i) a user input parameter from a user of the client device and (ii) an automatically generated salt parameter; encrypting the file using the file encryption key to form an encrypted copy of the file; and providing the salt parameter to an external storage system to externally store the salt parameter, access to data within the encrypted copy of the file requiring the salt parameter provided to the external storage system; wherein the external storage system includes a remote backup assembly which performs backup operations on behalf of multiple client devices; and wherein the method further comprises: while the file resides locally in the client device, sending the encrypted copy of the file to the remote backup assembly to backup the file in the remote backup assembly; wherein the salt parameter is a random number which is locally generated by the client device; wherein creating the file encryption key includes deriving the file encryption key based on the user input parameter and the random number; wherein the user input parameter is a user password obtained from the user of the client device; wherein the file encryption key is created from the user password and the random number; and wherein providing the salt parameter to the external storage system includes sending the salt parameter to the external storage system while withholding the user password from the external storage system in a secure mode which imposes responsibility to manage the user password on the user of the client device to decrypt the encrypted copy of the file.