Rapid restoring method for Word encrypted documents

Abstract

The invention discloses a rapid restoring method for Word encrypted documents. The method comprises steps as follows: step one, a secret key rainbow table of restored Word documents is established; step two, decryption secrete keys of the encrypted documents are decoded; step three, original plaintext documents are reconstructed by use of the decryption secrete keys and structure information of Word documents. The method has the positive effects as follows: the rainbow table for decrypting the secrete keys is only needed to be generated once, and the generated rainbow table is suitable for restoring all encrypted documents; restoring is not related to the complexity of encryption passwords of encrypted documents, and the defect that a long password cannot be cracked with an existing document cracking method is overcome; Word encrypted documents of version 2003 can be effectively restored, and the success rate reaches 99% or above; the encrypted documents can be rapidly restored, tests prove that the average restoring time of the encrypted documents is within 3 min under the computation ability of ordinary desktop computers (with the basic frequency being 3.0 GHz or above), and actual demands for real-time decryption can be well met.

Description

technical field [0001] The invention relates to a fast restoration method of a Word encrypted document. Background technique [0002] The Word office document developed by Microsoft Corporation is a word processing tool widely used by people at present, and the security and privacy protection of document content have become the most basic needs of users. Word documents use encryption technology to restrict access to documents. After encryption, only the correct password (also called password in daily life) can be viewed and edited. This provides the necessary security for user data. However, with the extensive use of passwords in various encryption applications, the situation that users forget passwords often occurs. If the password of some important Word documents is forgotten, the document cannot be opened, which will bring great trouble or loss to the user. On the other hand, the encrypted Word document also brought difficulties to the national security department in th...

AI Technical Summary

Problems solved by technology

[0010] (1) Different from the traditional document restoration method based on password cracking, this restoration method has nothing to do with the complexity of the password, and solves the problem that the encrypted document cannot be restored due to the inability to crack the current complex password

[0011] (2) It can restore plaintext documents within a certain time, solving the problem that the timeliness of current document cracking cannot meet the actual needs

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