An image encryption algorithm robust to post-encryption bitrate conversion

Akdağ, Sadık Bahaettin
In this study, a new method is proposed to protect JPEG still images through encryption by employing integer-to-integer transforms and frequency domain scrambling in DCT channels. Different from existing methods in the literature, the encrypted image can be further compressed, i.e. transcoded, after the encryption. The method provides selective encryption/security level with the adjustment of its parameters. The encryption method is tested with various images and compared with the methods in the literature in terms of scrambling performance, bandwidth expansion, key size and security. Furthermore this method is applied to the H.263 video sequences for the encryption of I-frames.


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Özcanli-Özbay, Özge Can; Yarman Vural, Fatoş Tunay; Department of Computer Engineering (2004)
In this thesis, a Content Based Image Retrieval (CBIR) system to query the objects in an image database is proposed. Images are represented as collections of regions after being segmented with Normalized Cuts algorithm. MPEG-7 content descriptors are used to encode regions in a 239-dimensional feature space. User of the proposed CBIR system decides which objects to query and labels exemplar regions to train the system using a graphical interface. Fuzzy ARTMAP algorithm is used to learn the mapping between f...
A Cascadable Random Neural Network Chip with Reconfigurable Topology
Badaroglu, Mustafa; Halıcı, Uğur; Aybay, Isik; Cerkez, Cuneyt (Oxford University Press (OUP), 2010-03-01)
A digital integrated circuit (IC) is realized using the random neural network (RNN) model introduced by Gelenbe. The RNN IC employs both configurable routing and random signaling. In this paper we present the networking/routing aspects as well as the performance results of an RNN network implemented by the RNN IC. In the RNN model, each neuron accumulates arriving signals and can fire if its potential at a given instant of time is strictly positive. Firing occurs at random, the intervals between successive ...
A compact cryptographic processor for IPSec applications
Kavun, Elif Bilge; Akyıldız, Ersan; Yalçın, Tolga; Department of Cryptography (2010)
A compact cryptographic processor with custom integrated cryptographic coprocessors is designed and implemented. The processor is mainly aimed for IPSec applications, which require intense processing power for cryptographic operations. In the present design, this processing power is achieved via the custom cryptographic coprocessors. These are an AES engine, a SHA-1 engine and a Montgomery modular multiplier, which are connected to the main processor core through a generic flexible interface. The processor ...
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Çelik, Coşkun; Bazlamaçcı, Cüneyt Fehmi; Department of Electrical and Electronics Engineering (2004)
IP multicasting is a method for transmitting the same information to multiple receivers over IP networks. Reliability issue of multicasting contains the challenges for detection and recovery of packet losses and ordered delivery of the entire data. In this work, existing reliable multicast protocols are classified into three main groups, namely tree based, NACK-only and router assisted, and a representative protocol for each group is selected to demonstrate the advantages and disadvantages of the correspond...
A new approach for better load balancing of visibility detection and target acquisition calculations
Filiz, Anıl Yiğit; Can, Tolga; Department of Computer Engineering (2010)
Calculating visual perception of entities in simulations requires complex intersection tests between the line of sight and the virtual world. In this study, we focus on outdoor environments which consist of a terrain and various objects located on terrain. Using hardware capabilities of graphics cards, such as occlusion queries, provides a fast method for implementing these tests. In this thesis, we introduce an approach for better load balancing of visibility detection and target acquisition calculations b...
Citation Formats
S. B. Akdağ, “An image encryption algorithm robust to post-encryption bitrate conversion,” M.S. - Master of Science, Middle East Technical University, 2006.