QR code using invisible watermarking in frequency domain

Nowadays, commercial activities on the internet and media need to be protected by increasing of security, using the 2D Barcode with a digital watermark in security field. This paper proposes that QR Code (Quick Response Code) is embedded with an invisible watermark by using Discrete-Cosine-Transform, or DCT for an information hiding (secret information) within the group through the QR Code image with invisible watermark. The encoding process used the DCT to allow QR Code image to be broken up into different frequency bands using block DCT based method; comparison between mid-band coefficients then embed with the invisible watermarking information into the middle frequency bands. The watermark extraction system determines a watermark in the QR Code image by reverse the embedded process from the invisible watermark. This QR Code image with invisible watermark preserves an information hiding text in the QR Code image.