**2. Proposed method**

Based on the integer wavelet transform (IWT), we propose two lossless data hiding methods, namely, a robust version and a high-capacity one. First, a robust lossless data hiding via the feature-based bit embedding (FBBE) algorithm is specified. Instead of embedding data bits directly into the IWT coefficient blocks, we use the FBBE algorithm to encode a block so that it can carry data bits and can be successfully identified later at the receiver. Then, a high-performance lossless data hiding scheme is presented to provide a large hiding storage by adjusting the location of each IWT coefficient in the host block. More specifically, the FBBE algorithm can be used to generate a robust lossless data hiding method. Whereas, the proposed smart adjustment of the IWT coefficients can be used to generate a high-performance lossless data hiding scheme.
