1. A method for embedding watermark into an image and detecting the watermark, comprising: generating a pseudo random sequence, the length of the pseudo random sequence is 2 n ; generating a watermark sequence by circular-shifting in a shift register said pseudo random sequence by the distance d; multiplying said watermark sequence by coefficient representing watermark embedding strength; and generating a watermark-embedded image in a frequency transformation domain by adding the multiplied watermark sequence to a wavelet-transformed original image; generating a watermark-embedded image in a spatial domain by inverse wavelet-transforming said watermark-embedded image generated in the frequency transformation domain; cross-correlating said watermark-embedded image generated in the spatial domain and said pseudo random sequence by circular-shifting in the shift register said pseudo random sequence; detecting a distance d′, wherein the distance d′ is a maximum cross-correlation value; and dividing the distance d′ by 2 m to retrieve a quotient, wherein the quotient is embedded information.