| 摘要 |
Data access protection in a system that can determine a passphrase for controlling access to a file, operate a hash function on the passphrase by a predetermined number of iterations to provide an intermediate passphrase, and send a request for an enhanced passphrase to a server in communication with the apparatus, where the request can include the intermediate passphrase. Subsequently, the disclosed computing system can receive, from the server, the enhanced passphrase, based on the intermediate passphrase in response to the request. The encrypted file header may include the adjusted iteration count where the case iteration can be modified by a random number, or by an exponential function of time, which is significantly smaller than the base iteration count. This reduces the effectiveness of rainbow tables. |
