Patent ID: 9699147
Date: 2017-07-04
CPC Classifications: H04L

Claim:
1. A method for encrypting a digital file, comprising the following steps: generating, when a user requests to download a specified digital file, a key, according to inherent information of the user, inherent information of a client terminal used by the user, and inherent information of the specified digital file; encrypting the specified digital file according to the key that has been generated; and performing decryption according to the key and a corresponding decryption procedure, after an encrypted digital file is downloaded at the client terminal used by the user; wherein the step of encrypting the specified digital file according to the key that has been generated comprises: encrypting content of the digital file segment by segment, each segment of the content of the digital file being encrypted with a sub key constituting a part of the key that has been generated; wherein encrypting content of the digital file segment by segment, each segment of the content of the digital file being encrypted with a sub key constituting a part of the key that has been generated comprises the following steps: step a): skipping a file header of the content of the digital file, and letting i=1; step b): reading, starting from the skipped file header, N step c): skipping M step d): judging whether encryption to all the content of the digital file has been completed, and ending the steps if yes; or letting i=i+1, and returning to step b) if no wherein N