An efficient method that can estimate PN sequence of direct sequence spread spectrum (DS-SS) signal is presented in a non-cooperative context

on this base

spread-spectrum hidden message can be extracted blindly.At first

the optimization model with the cumulative correlation value between estimate sequence and SS signal as the objective function is established

and then the PN sequence can be estimated by Genetic Algorithm.Finally

by analyzing the correlation between PN sequence and stego-signal

the hidden messmate can be extracted.The method has been carried out on PC

the experimental results show that

PN sequence estimation performance of the low-SNR DS-SS signal is good

and the extracted hidden message can be identificated.