PNG electronic invoice image watermark embedding and authentication method based on block sorting

Abstract

The invention discloses a watermark embedding and authentication method for PNG (Portable Network Graphic) electronic invoice image content protection. The method has the main steps that: a PNG electronic invoice image is blocked, and in addition, image blocks are divided into a key class, a uniform class and a nonuniform class according to the contents of the image blocks and whether changeable pixel points are contained or not; the contents of image blocks of RGB (Red Green Blue) three components are respectively encrypted, then, watermark information is generated, and corresponding watermark embedding positions are selected according to different component image block classes; and the authenticity of the image blocks is judged through comparing the consistency of image block reconstructing watermarks and extracted watermarks, in addition, a transverse neighborhood extending detection method is adopted for further improving the tamper detection performance, and finally, an authentication result of an electronic invoice to be detected is obtained through integrating the detection conditions of the RGB three components. The watermark embedding and authentication method has the advantages that the watermark invisibility is enabled to be realized, and meanwhile, the increase in the PNG image size is little; the tamper detection accuracy is high; the false detection rate is low; and the tamper such as replacing, adding, deleting and collaging can be effectively resisted.

Description

technical field [0001] The invention relates to a method for digital watermark embedding and tampering detection of a PNG electronic invoice image, which is used to verify the authenticity and integrity of the content of the electronic invoice. Background technique [0002] The "Online Invoice Management Measures" promulgated by the State Administration of Taxation came into effect on April 1, 2013, requiring all invoice-issuing units and individuals to issue online invoices to consumers. When the current online invoice is used as a financial accounting voucher, it is still necessary to print the electronic invoice on "specific paper". That is to say, the units and individuals that issue invoices still need to send the printed paper invoices to consumers by express, resulting in a waste of manpower and material resources. To this end, in June and December 2013, my country began to pilot electronic invoices in Beijing and Shanghai. If electronic invoices can be used as fina...

AI Technical Summary

Problems solved by technology

However, during image authentication, by comparing the consistency between the reconstructed watermark and the extracted watermark, only one image block will actually be tampered, but other associated image blocks will also be judged as tampered blocks, resulting in false detection.

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