Method for encrypting/deciphering residual quotiety amplitude value in H.264 standard video information

Abstract

The invention relates to a kind of encryption and deciphering method of remained difference coefficient breadth in H. 264 standard video information, it characterized in that: based on self adapting updating rule of remained difference coefficient breadth coding middle variable suffiXLength, adopting difference value absolute value which calculates current remained difference coefficient breadth and suffixLength self adapting updating threshold value, then based on the difference value absolute value, deciding bit number of last bit of the remained difference coefficient breadth which is to be encrypted, video code flow encrypted fulfill the H. 264 standard format. The characteristics of the invention are following: independent on video coder and decoder, video code flow encrypted fulfill the H. 264 standard; complexity of calculation is low, can fulfill the real time requirement of video information process and transmission; not affect the compression ratio; not affect video communication and network fault tolerant of video transmission; secrecy class can be realized; independent on concrete cryptogram arithmetic, it can use different international normal cryptogram arithmetic, the secrecy can achieve level that current technique can not decrypt.

Description

technical field [0001] The invention belongs to the field of video security communication, and specifically relates to an encryption and decryption method for residual coefficient amplitude in H.264 standard video information. Background technique [0002] With the wide application of various video, the security problem of video information is also becoming more and more prominent. Source encryption, that is, the encryption of the video content itself, is the main and more important means to solve the security of video information. The encryption of the video content itself can ensure that even if the illegal user obtains the video information, he cannot correctly decrypt and watch the original correct video image without the key. [0003] Because video information has massive data, in specific applications, such as in videophone or video conferencing applications, dozens of images must be transmitted per second. If a universal encryption algorithm for general information (...

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Problems solved by technology

[0006] 2) Keeping format information such as video syntax and semantics compatible with standards also keeps fixed fields such as various initial codeword format information in the video stream unchanged. These fields are widely known because they are disclosed in protocols or standards. If these fields are encrypted, it will also cause known plaintext attacks, which is not conducive to the security of video information.

[0014] However, the entire level_suffix cannot be directly encrypted, because the change of level_suffix will cause the change of the adaptive update of suffixLength, resulting in an error in judging the length of the codeword level_suffix when decoding the next residual coefficient amplitude codeword, that is, destroying If the code stream semantic format is changed, it will inevitably cause decoding failure

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