Data Hiding in a Halftone Image Using Hamming Code (15, 11)

This paper presents a data hiding technique for a halftone image. Each block of halftone bitmaps is transformed into a sequence of binary bits, and then regarded as a codeword. From the codeword, we can get a syndrome value. The XOR operation between a syndrome and 4- bits secret message is used to conceal 4-bits in the codeword. If the value of a XOR operation is not decimal zero, the position in a codeword should be flipped. In this way, one can hide a message. When every embedding procedure is finished, a sender transmits a stego halftone image to a receiver. A receiver can then extract secret data with a stego image, using a hamming code scheme. Using this procedure, we can conceal secret data in a halftone image and vice versa. Our proposed method is to hide 4-bits in a 4 × 4 block to flip a bit, is easy to implement, and achieves a high embedding capacity with good perceptual quality. It can be used to copyright and secret communications.