Patent ID: 11915336
Assignee: INDUSTRY-ACADEMIA COOPERATION GROUP OF SEJONG UNIVERSITY
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 8:
9. A method of verifying integrity of a Joint Photographic Experts Group (JPEG) image in which a watermark is embedded, the method comprising:
performing an entropy decoding on the JPEG image to generate quantized discrete cosine transform (DCT) coefficients;
determining target bits in a bit plane of the quantized DCT coefficients according to a predetermined rule and generating a plurality of groups of blocks (GOBs) having a tree structure based on a plurality of blocks in the bit plane such that each child GOB includes at least one target bit;
extracting a first watermark from the target bits;
generating a block identifying key (BIK) for each child GOB on the basis of the child GOB information including information about bits that are not included in the target bits in the child GOBs and the branch chain information of the child GOB, the metadata of the PEG image, and a user key, and
generating a random bit sequence (RBS) for each child GOB on the basis of the BIK for each child GOB as a second watermark; and
comparing the first watermark with the second watermark to verify the integrity of the image.