Digital watermark encrypting/decrypting method and system

Abstract

The invention discloses a digital watermark encrypting / decrypting method and system. According to the digital watermark encrypting / decrypting method and system, the digital watermark encrypting / decrypting algorithm is greatly simplified, the calculation amount of encrypting / decrypting is remarkably reduced, the encrypting / decrypting efficiency is improved, and the digital watermark can be ensuredto have extremely high robustness. The digital watermark encrypting method provided by the embodiment of the invention comprises the steps of: carrying out discrete cosine transformation on all the image blocks of a carrier picture to obtain a DCT (discrete cosine transformation) coefficient of the carrier picture, and extracting the DCT coefficient from an intermediate frequency band; digitalizing the information to be encrypted to obtain a corresponding two-dimensional array; mapping the two-dimensional array to the DCT coefficient of the intermediate frequency band according to a coefficient exchanging rule so as to attach the information to be encrypted into the carrier picture; and carrying out inverse DCT on the carrier picture attached with the information to be encrypted to obtainan encrypted picture.

Description

technical field [0001] The invention relates to the technical field of digital watermark information security, in particular to a digital watermark encryption and decryption method and system. Background technique [0002] As the scale of the Internet expands day by day, people enjoy more and more resources, and the anti-piracy of resources becomes more and more important. Digital watermarking information security technology is a hot technology that is developing very fast at present, and it intersects with image processing, digital communication, cryptography, and information security disciplines. [0003] In the digital watermarking technology, the data to be encrypted is embedded into the multimedia works, and these data need to be transformed before adding, and the transformed data is called digital watermarking. The digital watermark is added to the work as hidden information and does not affect the original work. The digital watermark is robust, that is, the original ...

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Problems solved by technology

[0005] However, there are still some problems in the existing digital watermarking algorithms. For example, the algorithm based on the space domain is not robust, and it is difficult to restore the original information when encountering interference or clipping; For the algorithm, the robustness is good, but the amount of data that can be embedded in the algorithm based on the spectrum domain is usually small, the encryption algorithm is usually fixed and complex, the calculation is large, and the encryption efficiency is low

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