The two issues of art image creation and data hiding are integrated into one and solved by a single approach in this study. An automatic method for generating a new type of computer art, called stained glass image, which imitates the stained-glass window picture, is proposed. The method is based on the use of a tree structure for region growing to construct the art image. Also proposed is a data hiding method which utilizes a general feature of the tree structure, namely, number of tree nodes, to encode the data to be embedded. The method can be modified for uses in three information protection applications, namely, covert communication, watermarking, and image authentication. Besides the artistic stego-image content which may distract the hacker's attention to the hidden data, data security is also considered by randomizing both the input data and the seed locations for region growing, yielding a stego-image which is robust against the hacker's attacks. Good experimental results proving the feasibility of the proposed methods are also included.

In this letter, we present an authentication and recovery scheme to protect images. The image blocks are DCT transformed and then encoded with different patterns. An optimal selection is adopted to find the best pattern for each block which results in better image quality. Both the recovery and check data are embedded for data protection. The experimental results demonstrate that our method is able to identify and localize regions having been tampered with. Furthermore, good image quality for both watermarked and recovered images are effectively preserved.

The traditional cryptographic hash functions are sensitive to even one-bit difference of the input message. While multimedia data always undergo compression or other signal processing operations, which lead to the unsuitability of multimedia authentication using cryptographic hash. The image hashing has emerged recently which captures visual essentials for robust image authentication. In this paper, we give a comprehensive survey of image hashing. We present an overview of various image hashing schemes and discuss their advantages and limitations in terms of security, robustness, and discrimination under different types of operations on the image.

We propose an asymmetric fragile watermarking technique that uses a number theoretic transform (NTT). Signature data is extracted from a watermarked image by determining correlation functions that are computed using the NTT. The effectiveness of the proposed method is evaluated by simulated detection of altering.

Image authentication is applied to protect the integrity of the digital image. Conventional image authentication mechanisms, however, are unfit for the palette-based color images. Palette-based color images such as GIF images are commonly used for media communications. This article proposes a palette-based color image authentication mechanism. This novel scheme can guarantee the essentials of general authentication schemes to protect palette-based color images. Morphological operations are adopted to draw out the tampered area precisely. According to the experimental results, the images embedded with the authentication data still can preserve high image quality; specifically, the new scheme is highly sensitive to altered areas.

In this study, a novel binary image authentication scheme is proposed, which can be used to detect any alteration of the host image. In the proposed scheme, the watermark is embedded into a host image using a Hamming-code-based embedding algorithm. A performance analysis shows that the proposed scheme achieves both smaller distortion and lower false negative rates than the previous schemes.

This paper presents a secure and simple content-based digital signature method for verifying the image authentication under JPEG, JPEG2000 compression and scaling based on a novel concept named lowest authenticable difference (LAD). The whole method, which is extended from the crypto-based digital signature scheme, mainly consists of statistical analysis and signature generation/verification. The invariant features, which are generated from the relationship among image blocks in the spatial domain, are coded and signed by the sender's private key to create a digital signature for each image, regardless of the image size. The main contributions of the proposed scheme are: (1) only the spatial domain is adopted during feature generation and verification, making domain transformation process unnecessary; (2) more non-malicious manipulated images (JPEG, JPEG2000 compressed and scaled images) than related studies can be authenticated by LAD, achieving a good trade-off of image authentication between fragile and robust under practical image processing; (3) non-malicious manipulation is clearly defined to meet closely the requirements of storing images or sending them over the Internet. The related analysis and discussion are presented. The experimental results indicate that the proposed method is feasible and effective.

Conventional authentication methods, proposed mainly for gray-scale and color images, are not appropriate for palette images, which usually contain simple contents with a limited number of colors. In this paper, a new approach is proposed to verify the integrity of palette images and to locate tampered regions without re-quantization and re-indexing processes. The proposed approach is based on a combined use of both the fragile watermarking and the digital signature approaches, taking the advantages of both approaches and avoiding their drawbacks. To protect a block of an image, authentication signals are first generated according to a secret key. Based on an embeddability property defined in the study, the pixels of each block are classified as embeddable or non-embeddable. Only the former ones are used to embed the authentication signals. A corresponding digital signature is generated as well to compensate the possibly limited embedding capacity of the embeddable pixels that are insufficient in number. To authenticate a block, the recovered authentication signals, yielded from the extracted watermark and the received digital signature, are compared with the one generated according to the correct secret key, to prove the block's legitimacy. The effectiveness and the security of the proposed method are analyzed and tested with a variety of palette images. The results indicate that the proposed method can offer high authentication accuracy as well as maintain a good tradeoff between the authentication signal portability and the resulting image quality.

This letter presents a novel quandtree-based image authentication technique especially suitable for the content authentication of high quality required digital images. The host image and the hiding marks generate quadtrees which record the information of host images. Any malicious tamper to the image is reflected from the recovered marks. Compared to other authentication schemes based on the fragile watermarking technique, the host image is not at all modified and the detection to malicious tamper is sensitive.