This thesis describes a novel technique for embedding watermark bits into digital audio signals. The proposed method is based on the multi-layered hwork algorithm on the wavelet domain and does not need the original audio signal in the watermark detection. It uses the wavelet transform generated by the low-pass analysis filter $h_n$ whose length is 2 and high-pass synthesis filter $g_n$ whose length is 10 to meet a fast synchronization between watermark embedding and detection processes. It puts watermarks in the detail parts. Several simulation results show that the proposed method is robust against various signal manipulations such as MPEG/Audio layer 3 compression and puts much more bits than the previous method.