Share Audio Cryptography Using DCT Transform

number: 
3398
English
department: 
Degree: 
Author: 
Sarah Saad Ali Albaghdady
Supervisor: 
Dr. Abeer M. Yousif
year: 
2014

An Effective and secure protection of sensitive information is the primary concern in communication systems or network storage systems, it is important for any information process to ensure data is not being tampered. To achieve confidentiality and integrity of multimedia information, various Secret Sharing Schemes (SSS) have been developed.This thesis presents a (2,n) threshold Secret Sharing Scheme, which is one of the types of SSS and a special  kind of  (k, n) threshold scheme. This scheme share a secret file among n participants, and any two participants could cooperate to reconstruct the secret file, otherwise participants could get nothing. The proposed scheme is designed to solve the problem of increasing share size in most threshold secret sharing schemes besides guaranteeing security with low complexity..The proposed scheme prototype consists of two modules:  Encoder and Decoder, the input to the former is plain audio data (.WAV) while the output is n shares. Encoder is passes through two stages: compression and encryption. Compression is achieved by performing Discrete Cosine Transformation DCT, Quantizing, Run-Length Encoding, and Shifting Coding stages sequentially. While encryption is acquired by diffusion, implementing Random Coefficients generating and Share Functions generating stages consecutively.The performance of the proposed scheme was tested, using some fidelity measures such as Mean Square Error (MSE) and Peak Signal Noise Ratio (PSNR) to measure the rate of error while Compression Ratio (CR) is used to measure the compression efficiency. The test result shows encourage results.