Behavior study of EDEU optical code for FE-OCDMA system

The increase in the cardinality of the frequency encoding-optical code division multiple access (OCDMA) system directly affects the length of the optical code, which leads us to find a less expensive solution. In this work, I propose an improved version of the diagonal eigenvalue Unit code (DEU) called Enhanced diagonal eigenvalue Unit code (EDEU) that is much easier in terms of construction and short in code length compared to the DEU code. The results found showed that the performance of the EDEU code exceeds the DEU code in terms of bit error rate (BER), and allowed us to multiplex about 15 more users when using the EDEU code compared to the system using the DEU code. As a result, the EDEU code is very suitable for use in access and OCDMA systems and it can be seen as a strong competitor to existing codes.

Frequency-hiding order-preserving encryption with small client storage

The range query on encrypted databases is usually implemented using the order-preserving encryption (OPE) technique which preserves the order of plaintexts. Since the frequency leakage of plaintexts makes OPE vulnerable to frequency-analyzing attacks, some frequency-hiding order-preserving encryption (FH-OPE) schemes are proposed. However, existing FH-OPE schemes require either the large client storage of size O ( n ) or O (log n ) rounds of interactions for each query, where n is the total number of plaintexts. To this end, we propose a FH-OPE scheme that achieves the small client storage without additional client-server interactions. In detail, our scheme achieves O ( N ) client storage and 1 interaction per query, where N is the number of distinct plaintexts and N ≤ n . Especially, our scheme has a remarkable performance when N ≪ n . Moreover, we design a new coding tree for producing the order-preserving encoding which indicates the order of each ciphertext in the database. The coding strategy of our coding tree ensures that encodings update in the low frequency when inserting new ciphertexts. Experimental results show that the single round interaction and low-frequency encoding updates make our scheme more efficient than previous FH-OPE schemes.

A Novel Method of Designing an all Optical 3-Bit Asynchronous Counter

In digital signal processing and data communication system in optical domain it is paramount important to count the pulse number of any device or processor and hence optical counter for fast counting. In this letter the authors propose a new method to implement an all-optical 3- bit asynchronous binary counter comprising all-optical T flip flops which works based on the polarization switching characteristics of SOA, and frequency encoded data have been used for communication purpose. Use of Frequency encoding technique in the proposed scheme makes it attractive and effective one in various aspects in wave division multiplexing based communication network. Simulation aided results support the practicability of the proposed scheme.