Image security system using hybrid cryptosystem

This work presents and describes a novel method to hide messages in images in a hybrid manner, as steganography is combined with quantum cryptography. Through stimulating and implementing this hybrid approach, the least significant bit (LSB) substitution is employed for hiding secret messages within cover images that consist of three bands (Red, Green and Blue), after which the output is encrypted using quantum one-time pad encryption. The models are illustrated explicitly and tested. In addition, the test analysis uses a steganalysis tool called StegExpose to detect LSB steganography in images. The experimental results proved that the image hiding is reliably secure and undetectable, and hence the proposed new hybrid model provides a sufficient security level as well as we have tested the proposed system using robust state-of- the-art steganalysis techniques and found the low payload threshold maintained in the proposed system produces a high margin of communication security safety. No payload files were detected (0% detections), despite each file containing the entire content of the information as embedded text

High capacity steganographic method based upon JPEG

The two most important aspects of any image-based steganographic system are the quality of the stegoimage and the capacity of the cover image. This paper proposes a novel and high capacity steganographic approach based on Discrete Cosine Transformation (DCT) and JPEG compression. JPEG technique divides the input image into non-overlapping blocks of 8x8 pixels and uses the DCT transformation. However, our proposed method divides the cover image into nonoverlapping blocks of 16x16 pixels. For each quantized DCT block, the least two-significant bits (2-LSBs) of each middle frequency coefficient are modified to embed two secret bits. Our aim is to investigate the data hiding efficiency using larger blocks for JPEG compression. Our experiment result shows that the proposed approach can provide a higher information hiding capacity than Jpeg-Jsteg and Chang et al. methods based on the conventional blocks of 8x8 pixels. Furthermore, the produced stego-images are almost identical to the original cover images

Blindspot: Indistinguishable Anonymous Communications

Communication anonymity is a key requirement for individuals under targeted surveillance. Practical anonymous communications also require indistinguishability - an adversary should be unable to distinguish between anonymised and non-anonymised traffic for a given user. We propose Blindspot, a design for high-latency anonymous communications that offers indistinguishability and unobservability under a (qualified) global active adversary. Blindspot creates anonymous routes between sender-receiver pairs by subliminally encoding messages within the pre-existing communication behaviour of users within a social network. Specifically, the organic image sharing behaviour of users. Thus channel bandwidth depends on the intensity of image sharing behaviour of users along a route. A major challenge we successfully overcome is that routing must be accomplished in the face of significant restrictions - channel bandwidth is stochastic. We show that conventional social network routing strategies do not work. To solve this problem, we propose a novel routing algorithm. We evaluate Blindspot using a real-world dataset. We find that it delivers reasonable results for applications requiring low-volume unobservable communication.Comment: 13 Page