Javaid A. Sheikh

Robust and blind watermarking technique in DCT domain using inter-block coefficient differencing

In this paper, a robust blind watermarking technique, based on block-based DCT coefficient modification is proposed. The difference between two DCT coefficients of the adjacent blocks at the same position is calculated. Depending upon the watermark bit to be embedded; this difference is brought in a particular predefined range which is achieved by modifying one of the two DCT coefficients. The amount of modification to a DCT coefficient of a block depends upon the scaling variable, DC coefficient and median of certain zig-zag ordered AC coefficients of that block. The robustness of the proposed scheme has been examined for various singular and hybrid attacks. Comparison results reveal that the proposed technique has a higher degree of robustness against various singular and hybrid attacks. Further a watermark of good quality is extracted even after various simultaneous attacks on the system.

Data hiding in scrambled images: A new double layer security data hiding technique

The contemporary multimedia and communication technology has made it possible to replicate and distribute digital media easier and faster. This ease of availability causes the problem of exposing transmitted digital data on the network with the risk of being copied or intercepted illegally. Many cryptographic techniques are in vogue to encrypt the data before transmission to avert any security problems. However, disguised appearance of the encrypted data makes the adversary suspicious and increases the chances of malicious attack. In such a scenario data hiding has received significant attention as an alternate way to ensure data security. This paper presents a data hiding technique based on the concepts of scrambling and pseudorandom data hiding; to provide a data hiding system with two layer security to the embedded data, and good perceptual transparency of the stego images. The proposed system uses the novel concept of embedding the secret data in scrambled (encrypted) cover images. The data embedding is carried out in the Intermediate Significant and least significant bit planes of encrypted image at the predetermined locations pointed to by Pseudorandom Address Space (PAS) and Address Space Direction Pointer (ASDP). Experimental results prove the efficacy of scheme viz-a-viz various parameters of interest.

Information hiding in medical images: a robust medical image watermarking system for E-healthcare

Electronic transmission of the medical images is one of the primary requirements in a typical Electronic-Healthcare (E-Healthcare) system. However this transmission could be liable to hackers who may modify the whole medical image or only a part of it during transit. To guarantee the integrity of a medical image, digital watermarking is being used. This paper presents two different watermarking algorithms for medical images in transform domain. In first technique, a digital watermark and Electronic Patients Record (EPR) have been embedded in both regions; Region of Interest (ROI) and Region of Non-Interest (RONI). In second technique, Region of Interest (ROI) is kept untouched for tele-diagnosis purpose and Region of Non-Interest (RONI) is used to hide the digital watermark and EPR. In either algorithm 8 × 8 block based Discrete Cosine Transform (DCT) has been used. In each 8 × 8 block two DCT coefficients are selected and their magnitudes are compared for embedding the watermark/EPR. The selected coefficients are modified by using a threshold for embedding bit a ‘0’ or bit ‘1’ of the watermark/EPR. The proposed techniques have been found robust not only to singular attacks but also to hybrid attacks. Comparison results viz-a - viz payload and robustness show that the proposed techniques perform better than some existing state of art techniques. As such the proposed algorithms could be useful for e-healthcare systems.

A secure and robust information hiding technique for covert communication

The unprecedented advancement of multimedia and growth of the internet has made it possible to reproduce and distribute digital media easier and faster. This has given birth to information security issues, especially when the information pertains to national security, e-banking transactions, etc. The disguised form of encrypted data makes an adversary suspicious and increases the chance of attack. Information hiding overcomes this inherent problem of cryptographic systems and is emerging as an effective means of securing sensitive data being transmitted over insecure channels. In this paper, a secure and robust information hiding technique referred to as Intermediate Significant Bit Plane Embedding (ISBPE) is presented. The data to be embedded is scrambled and embedding is carried out using the concept of Pseudorandom Address Vector (PAV) and Complementary Address Vector (CAV) to enhance the security of the embedded data. The proposed ISBPE technique is fully immune to Least Significant Bit (LSB) removal/replacement attack. Experimental investigations reveal that the proposed technique is more robust to various image processing attacks like JPEG compression, Additive White Gaussian Noise (AWGN), low pass filtering, etc. compared to conventional LSB techniques. The various advantages offered by ISBPE technique make it a good candidate for covert communication.

Data hiding in intermediate significant bit planes, a high capacity blind steganographic technique

The availability of relatively inexpensive digital products coupled with the promise of higher bandwidth and quality of service (QoS) for both wired and wireless communication networks have made it possible to create, replicate, transmit, and distribute digital data without any loss in quality. In such a scenario steganography has received huge attention from the research community round the globe, as it has been found useful for information security and under cover communication. Stegnography refers to covert communication for transfer of confidential information over a communication channel. This paper presents a high capacity stegnographic technique in which secret data is embedded in Intermediate Significant Bit planes of the cover image. The data to be embedded is broken down in blocks of relatively decreasing lengths and each block is embedded in the cover media under control of a highly secure key. This work shows attractive results with respect to imperceptibility and capacity when compared with a few reported techniques in addition to providing adequate data security.

Hiding in encrypted images: a three tier security data hiding technique

This paper presents a new crypto domain data hiding technique based on Intermediate Significant Bit Plane Embedding (ISBPE). The cover image is encrypted; the information to be secured is scrambled, and then embedded in the Intermediate Significant Bit (ISB) planes of encrypted cover image, at the locations determined by a Pseudorandom Address Vector (PAV). The pseudorandom embedding of the scrambled data in the ISB planes of encrypted image results in a three tier security of the data to be secured. The ISBPE embedding results in an important advantage that the proposed scheme becomes completely robust to commonly employed attack of Least Significant Bit (LSB) removal/replacement. A novel concept of embedding a very small size fragile watermark in addition to the secret information has been used which facilitates early tamper detection. This feature could save crucial processor time in critical situations of national security issues/warfare etc. Experimental results show that the proposed scheme is more robust to various signal processing attacks like Joint Picture Expert Group compression, Additive White Gaussian Noise and ‘salt and pepper’ noise as compared to conventional LSB based embedding techniques. Comparison results with some well-known techniques show that besides providing high degree of security and robustness to various malicious attacks the proposed technique is capable of embedding a fairly large amount of secret data in the host image while maintaining a good stego-image quality.

Hiding clinical information in medical images

A new high capacity and reversible data hiding scheme for e-healthcare applications has been presented in this paper. Pixel to Block (PTB) conversion technique has been used as an effective and computationally efficient alternative to interpolation for the cover image generation to ensure reversibility of medical images. A fragile watermark and Block Checksum (computed for each 4×4 block) have been embedded in the cover image for facilitating tamper detection and tamper localization, and hence content authentication at receiver. The EPR, watermark data and checksum data has been embedded using Intermediate Significant Bit Substitution (ISBS) to avoid commonly used LSB removal/replacement attack. Non-linear dynamics of chaos have been put to use for encrypting the Electronic Patient Record (EPR)/clinical data and watermark data for improving the security of data embedded. The scheme has been evaluated for perceptual imperceptibility and tamper detection capability by subjecting it to various image processing and geometric attacks. Experimental results reveal that the proposed system besides being completely reversible is capable of providing high quality watermarked images for fairly high payload. Further, it has been observed that the proposed technique is able to detect and localise the tamper. A comparison of the observed results with that of some state-of-art schemes show that our scheme performs better.

Information hiding in edges: A high capacity information hiding technique using hybrid edge detection

The multimedia security is becoming more and more important as the data being exchanged on the Internet is increasing exponentially. Though cryptography is one of the methods which is used to secure the data during transit, but the camouflaged appearance of the scrambled data alerts the adversary about some critical information being shared. In such a scenario, steganography has been used as an alternate solution to secure the secret information. In this paper a color image steganographic algorithm based on hybrid edge detection is proposed. The color image is partitioned into constituent Red (R), Green (G) and Blue (B) planes. Hybrid edge detection is used for finding the edge and non-edge pixels of Green and Blue planes of cover image. The Green and Blue planes are used for hiding the data while Red plane holds the pixel status (whether edge or non-edge) of these planes. The RC4 encryption algorithm is used to encrypt secret message before embedding it in the cover image to enhance security of the secret data. A fragile watermark/logo (whose size is less than 1% of total secret data) has been embedded, besides secret data in the cover image, to facilitate content authentication and early tamper detection. At the receiver, firstly logo is extracted. If it is same as one embedded at transmitter, indicating that secret data has not been altered during transit, secret data is extracted. Otherwise (if extracted logo is not same as used at input) the receiver does not waste critical time to extract compromised data but sends an automatic retransmission request. Experimental investigations reveal that the proposed scheme is capable of providing high quality of stego-images for a fairly high pay load. A comparison of the proposed technique with some state of art schemes substantiates the above arguments.

A high capacity data hiding scheme based on edge detection and even-odd plane separation

In this paper a high capacity data hiding technique based on hybrid edge detection and even-odd pixel separation is proposed. The even-odd sub planes of Red, Green and Blue of the cover image are extracted then Blue and Green channel sub planes are utilized for hiding the secret data while Red channel sub planes are used to hold the status (edge or non-edge) of the pixels of Green and Blue channel sub planes. The experimentation has been carried out for different capacities of data bits and the results are compared with a state of art data hiding technique which reveals that the proposed technique has high capacity. Further good quality stego-images are obtained.

On the realization of a spatial domain data hiding technique based on intermediate significant bit plane embedding (ISBPE) and Post Embedding Pixel Adjustment (PEPA)

Information security assumes a paramount importance in contemporary digital age. Data hiding in images has flourished in recent years as an important field for information security. An Intermediate Significant Bit (ISB) plane based data hiding technique is investigated and presented in this paper. The data to be embedded in a cover image has been scrambled, and embedding has been carried out at the address locations pointed to by Pseudorandom Address Vector (PAV). The perceptual degradation of the image caused due to embedding in ISB planes has been taken care of by using Post Embedding Pixel Adjustment (PEA) technique. The pseudorandom embedding of encrypted data provides a two tier of security to the embedded secret data. The comparison of the proposed technique with an existing data hiding scheme shows that proposed technique is capable of providing better quality stego-images even if the payload is slightly more. This is validated by an improvement in PSNR by about 3dB. Further, an important advantage offered by this technique is that the embedded data is not vulnerable to LSB removal/replacement attack as data is embedded in ISB planes.