Computer network routing is performed based on routing protocol decisions. Open Shortest Path First OSPF is the most known routing protocol. It suffers from congestion problem since it generally uses single (least cost) path to deliver information. Some times OSPF delivers information using more than one path in the case of more than one path have the same cost value. This condition is rarely achieved in normal cases. In this work OSPF is developed to distribute information load across multiple paths and makes load distribution as general case for the routing protocol. The modification supposes no protocol replacement and uses the existing protocol facilities. This makes faster information delivery, load balancing, less congestion, and with little modification on the built in OSPF functions. Disjoint paths are calculated then the costs of the best set of them are adapted using approporate ratio.
In this work, a new image encryption method using a combined multilevel permutation with stream cipher is proposed. In the permutation algorithm, image is divided into blocks in each level and its blocks are rearranged by using pseudorandom permutation method. A new non linear stream cipher algorithm is also proposed that is based on combining several keys generated by Linear Feedback Shift Register (LFSR). The results shown that the proposed algorithm has a high security feature and it is efficient for image encryption. Practical tests proved that the proposed encryption algorithm is robust, provides high level of security and gives perfect reconstruction of the decrypted image.
In this work a new hiding system is proposed. It is based on Least Significant Bits (LSB) embedding of secrete image into another cover image. The proposed hiding algorithm embeds the secrete image bits in the least significant bits of the cover image pixels such that the number of secrete image bits that are embedded in least significant bits of cover image pixel is variable and determined randomly. Such cover image pixel may contain no secrete information bit, one bit, two bits , or three bits according to the pseudo random number generator that generates integer numbers randomly between 0 and 3. The resulting image (the cover image within which the secret image is hidden) is called stego_image. Stego_image is closely related to the cover image and does not show any details of the secret information. It ensures that the eavedroppers will not have any suspicion that message bits are hidden in the image. The proposed system achieves perfect reconstruction of the secret message.
This work implying the design of hiding system that hides a gray scale image into another gray scale image using two-dimensional wavelet packet transform. The proposed hiding scheme uses Wavelet Packet Transform (WPT) to embed data elements of the secret image in different frequency bands of the cover image. The data elements of the secrete image are placed within DWT subspaces after simple treatment in order to reduce its significance on the resulting image and to increase security. The resulting image (the cover image within which the secret image is hidden) is called stego_image. Stego_image is closely related to the cover image and does not show any details of the secret image. The proposed system achieves perfect reconstruction of the secret image. All programs in this work is written by MATLAB 7.