Arithmetic encoding

In this paper, an enhanced Riveset Shamir Adleman (RSA) encryption scheme with data compression features based on Residue Number Systems (RNS) has been proposed and implemented. This scheme is implemented using the moduli set,. The scheme has two level of encryption and a two level of decryption to form a double layer public key encryption scheme. The first level comprises the classical RSA encryption algorithm and in the second layer, RNS number representation is utilised. Mixed Radix Conversion is employed in the first level of decryption and in the second level; the classical RSA decryption process is used. This will ensure a secured data transmission of messages of varying lengths. The private key length is further enhanced as the moduli set are part of the private key for decryption processes. The residues which form the basis of the transmitted cipher text are smaller in terms of number of bits than the cipher text generated from the classical RSA encryption scheme. This will increase the rate of data transmission in the communication channel.

In this paper, we present a novel video coding approach which provides the functionality of fine granular bitstream scalability. The proposed progressive texture video coding scheme (PTVC) consists of two parts, the current ITU-T H.26L test model for coding macroblock mode and motion information only and a new technique for progressively coding all intra and inter texture information thus providing an embedded bitstream. It can still be decoded with moderate quality degradation in case of partial loss of the bitstream. It is therefore well suited for multicast or broadcast scenarios where time varying or different fixed bitrates shall be provided to the clients as no transcoding or multiple coding process is required.

Set Partitioning in Hierarchal Trees (SPIHT) is an efficient method for compressing images under low bit rates. No List SPIHT (NLS) and Wavelet Based Block Tree Coding (WBTC) are two enhanced algorithms of SPIHT. The WBTC algorithm works on blocks instead of pixels in SPIHT. The size of root block in WBTC varies from one step to another. This reduces the memory requirement to a great extent. NLS uses markers instead of lists used for the storage of coefficients in SPIHT. The three lists used in SPIHT to manage the significant coefficients grow exponentially with each step as more number of coefficients is tracked. Due to this feature SPIHT algorithm requires a lot of memory management and hence it is complex for hardware implementation. But the 8 different markers used in NLS removes this drawback of original algorithm. Listless Block Tree Coding algorithm (LBTC) is evolved by combining the WBTC and NLS algorithms. In this algorithm image compression is performed on the block basis ...

Recently, Yang and Kieffer' proposed a novel lossless grammar-based data compression algorithm, called the YK algorithm, in which a greedy sequential grammar transform is applied to the original data to construct an irreducible context free grammar, which is encoded indirectly by using an arithmetic coder. The YK algorithm has been shown to be universal for the class of stationary, ergodic sources. Experimental results show that the YK algorithm significantly outperforms other commonly used sequential lossless data compression algorithms such as Lempel-Ziv types of codes. Moreover, the YK algorithm is effective on a virtually unlimited range of data sizes. The basic implementation of the YK encoding algorithm consists of a sequentially iterative application of three fundamental steps-Parsing, Arithmetic Encoding, and Updating. The parsing operation searches for the longest prefix of the remaining part of the original data sequence that is representable by the current grammar. The arithmetic encoding operation encodes the parsed phrase using frequency counts over a dynamic alphabet. The updating operation uses the parsed substring to update the grammar and the frequency counts. This paper proposes five modifications of the basic YK algorithm, motivated by applications of the algorithm to the internet transmission of web-data: 1. Fast YK encoder: The parsing operation is a major step of the YK algorithm, which can contribute to a significant portion of the overall time taken by the encoder. A variant of the trie data structure, which captures the structure of the context-free grammar in a non-redundant manner, is proposed for fast parsing. This is applicable for real-time compression of IP datagrams, particularly at high data rates. 2. Pre-defined source statistics: Known source statistics can be exploited to improve compression efficiency, which is particularly effective for small IP datagrams with a known structure, such as NNTP datagrams. 3. Pre-defined grammar: Starting with a "typical" pre-defined grammar can significantly improve the compression efficiency for applications such as HTML web-page compression, because HTML responses originating at a given server tend to have identical layout and similar content, in addition to having standard HTML tags and keywords. 4. Memory constrained implementation: During YK compression, as the length of the data sequence increases, the grammar also continues to grow in size, which can potentially exhaust the available memory in the system. This paper proposes a way to check memory requirement by reusing variables in the grammar, once a user-chosen limit on grammar size is reached. 5. Error handling capability: The paper identifies all possible contingencies that can arise when an erroneous bit-stream is fed to the YK decoder, and provides explicit ways to handle these. This is important in applications where compressed IP datagrams are transmitted over unreliable links.

Mobile communication devices have become popular tools for gathering and disseminating information and data. When sensitive information is exchanged using SMS, it is crucial to protect the content from eavesdroppers as well as ensuring that the message is sent by a legitimate sender. Using an encryption technique to secure SMS data increases its length and accordingly the cost of sending it. This paper provides a hybrid compression encryption technique to secure the SMS data. The proposed technique compresses the SMS to reduce its length, then encrypts it using RSA algorithm. A signature is added to the encrypted SMS for signing it to differentiate it from other SMS messages in SMSINBOX. The experimental results which are based on Symbian OS show that the proposed technique guarantees SMS data security without increasing its size.

Mobile communication devices have become popular tools for gathering and disseminating information and data. When sensitive information is exchanged using SMS, it is crucial to protect the content from eavesdroppers as well as ensuring that the message ...

This paper considers different aspects related to two different but not opposite direction-Data Compression and Cryptography. In this paper a brief review of both of these branches-compression and encryption, need of data compression and data encryption has been discussed. Also, the need of integrating these two branches has been addressed. There occurs a problem of the order of applying these two processes i.e.; Compression should be applied first before Encryption or Encryption should be applied first before compression. This paper discusses this issue of order also of these two processes. Public key cryptography, also called asymmetric encryption, uses a pair of keys for encryption and

This paper reports about the survey of various techniques available in an encryption and also in compression technique. It is mainly analyzing the existing encoding and compressed cryptosystem together as a literature survey. It is also discussed about the security issues of using various encryption technique and compression technique to reduce the size of plain text as well as to increase the transmission speed of plain text from one end to other end. This survey analyses several encryption technique, compression technique and also various literature paper so that it provides an idea for efficient integrated methods using compressed crypto system for future work .

This work deals with encoding algorithm that conveys a message that generates a "compressed" form with fewer characters only understood through decoding the encoded data which reconstructs the original message. The proposed factorization techniques in conjunction with lossless method were adopted in compression and decompression of data for exploiting the size of memory, thereby decreasing the cost of the communications. The proposed algorithms shade the data from the eyes of the cryptanalysts during the data storage or transmission.

Data compression technique such as Huffman
coding, arithmetic coding, Lempel-Ziv-Welch (LZW)
method and others has been playing a vital role in the area
of data transmission for reducing time usage during
retrieving and transmitting data. However, this technique
does not prevent data which contain secret information
from being tampered or hacked by malicious attacks even
in limited area network environment. Apart from the need
of reducing data volume, an implementation of encryption
is an important concern in order to transmit data over
perfect security. This paper presents feasible approach in
minimizing quantity of data and ensuring its security; data
is compressed using a lossless algorithm, i.e. Huffman
coding and then the compressed data is encrypted using
symmetric encryption, AES algorithm. In this work, key
exchange concept is also proposed based on Diffie Hellman
Key Exchange (DHKE) which is used to exchange secret
key for data encryption and decryption. The data is
transferred in a local network between two computers
through simple file transfer protocol known as Trivial File
Transfer Protocol (TFTP). This protocol has been used
widely for updating and transferring files especially to
embedded devices and it would provide more benefit if
security features were incorporated into this protocol.
Thus, a lightweight security strategy which includes
compression and encryption is an efficient solution to the
security issue and to reducing file sizes in this type of
environment. Experimental results based on proposed
methodology are provided to analyze execution time of
transmitting compressed-encrypted data and percentage
reduction of file space.

Mobile communication devices have become popular tools for gathering and disseminating information and data. When sensitive information is exchanged using SMS, it is crucial to protect the content from eavesdroppers as well as ensuring that the message is sent by a legitimate sender. Using an encryption technique to secure SMS data increases its length and accordingly the cost of sending it. This paper provides a hybrid compression encryption technique to secure the SMS data. The proposed technique compresses the SMS to reduce its length, then encrypts it using RSA algorithm. A signature is added to the encrypted SMS for signing it to differentiate it from other SMS messages in SMSINBOX. The experimental results which are based on Symbian OS show that the proposed technique guarantees SMS data security without increasing its size.