Method for dynamically extending additional information of transparent encrypted file

Abstract

The invention discloses a method for dynamically extending additional information of a transparent encrypted file. The transparent encrypted file comprises an additional information fixed storage part and a file content part, wherein the additional information fixed storage part has fixed length and is used for storing the additional information; and the file content part is used for storing the content of the file. In the method, the length of the additional information is calculated when the transparent encrypted file is established; when the length of the additional information exceeds that of the additional information fixed storage part, an additional information extended storage part is distributed; and relative position information and length information of the extended storage part are stored into the fixed storage part, so that storage of the additional information of the transparent encrypted file can be dynamically extended and flexibility of a transparent encryption technique is improved.

Description

technical field [0001] The invention relates to the field of computer file encryption and decryption, in particular to a method for dynamically expanding additional information of transparent encrypted files. Background technique [0002] With the deepening of enterprise information application, most of the work of enterprise employees is completed on the computer, and various reports, reports, design drawings and other important results exist in the form of electronic files, and electronic documents are easy to pass through emails and mobile storage devices. Leakage through other channels has brought great security risks to enterprises. In order to prevent the leakage of confidential documents, one of the commonly used methods is to encrypt the confidential documents, so that even if the files are leaked, unauthorized users cannot open the documents. There are two commonly used methods for document encryption: one is to identify the file format (such as Office documents), ...

AI Technical Summary

Problems solved by technology

The advantage of using a fixed-length additional area is that the processing is relatively simple, but the disadvantage is that the scalability is insufficient. If encryption and decryption need to use more file additional information, especially the length occupied by the authorization information of the file may not be fixed. If a file The more people to authorize, the more controls the storage of authorization information needs to occupy, beyond the fixed length of additional information, the existing technology will not be able to handle it, so some features can only be sacrificed (such as limiting the number of entries of authorization information), Do things as simple as possible in the transparent encryption and decryption driver

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