This paper discusses the problem of using data compression for encryption. We first propose an algorithm for breaking a prefix-coded file by enumeration. Based on the algorithm, we respectively analyze the complexity of breaking Huffman codes and Shannon-Fano-Elias codes under the assumption that the cryptanalyst knows the code construction rule and the probability mass function of the source. ...

This paper presents the design and implementation of an AAC-class digital audio decoder and associated playback system on Microchip’s 16-bit, fixed-point dsPIC microcontroller. Unlike common student “MP3-player” projects that use dedicated decoder chips, one microcontroller handles everything here including I/O, decoding and the user interface. Data read from a flash card is decoded: Huffman co...

Shannon (1948) has shown that a source (U, P, U) with output U satisfying Prob (U = u) = Pu, can be encoded in a prefix code C = {cu : u ∈ U} ⊂ {0, 1} * such that for the entropy H(P) = u∈U −pu log pu ≤ pu||cu|| ≤ H(P) + 1, where ||cu|| is the length of cu. We use a prefix code C for another purpose, namely noiseless identification , that is every user who wants to know whether a u (u ∈ U) of h...

This paper presents an efficient and general framework for code compression for embedded systems. The method is based on simple Huffman encoding, but where limited yet powerful higher-order correlations are captured and exploited by using architecture-oriented models. The proposed symbol formation, modeling and encoding steps together achieve high-quality code compression, yet the decoding proc...

Variable-length codes (VLCs) improve coding performance using statistical characteristics of source symbols; however, VLCs have disastrous effects from bit errors in noisy transmission environments. In order to overcome problems with VLCs, reversible variable-length codes (RVLCs) have been introduced as one of the error resilience tools due to their error recovering capability for corrupted vid...

38 Abstract— Compression is a technology for reducing the quantity of data used to represent any content without excessively reducing the quality of the picture. The need for an efficient technique for compression of images ever increasing because the raw images need large amounts of disk space seems to be a big disadvantage during transmission & storage. Compression is a technique that makes s...

Image steganography is the art of hiding information into a cover image. This paper presents a novel technique for Image steganography based on DWT, where DWT is used to transform original image (cover image) from spatial domain to frequency domain. Firstly two dimensional Discrete Wavelet Transform (2-D DWT) is performed on a gray level cover image of size M × N and Huffman encoding is perform...

In this paper we discuss a variation of the classical Huffman coding problem: finding optimal prefix-free codes for unequal letter costs. Our problem consists of finding a minimal cost prefix-free code in which the encoding alphabet consists of unequal cost (length) letters, with lengths α and β. The most efficient algorithm known previously required O(n) time to construct such a minimal-cost s...

The idea of q cyclotomic cosets modulo n due to carry Huffman and Vera pless is considered in the context of linear codes of length n over ( ) GF q where m q p  , p is a prime, 1 m  . An explicit formula for the number of q cyclostomes cosets modulo is obtained as an application of the classical Burnsides lemnra. The formula for the number of cyclic codes in   ( 1) n n q R F x x   is dedu...

Lossless compression is studied for a countably infinite alphabet source with an unknown, off-centered, two-sided geometric (TSG) distribution, which is a commonly used statistical model for image prediction residuals. In this paper, we demonstrate that arithmetic coding based on a simple strategy of model adaptation, essentially attains the theoretical lower bound to the universal coding redun...