The present invention relates to methods for protecting a data signal using the following techniques: applying a data reduction technique to reduce the data signal into a reduced data signal; subtracting the reduced data signal from the data signal to produce a remainder signal; embedding a first watermark into the reduced data signal to produce a watermarked, reduced data signal; and adding the watermarked, reduced data signal to the remainder signal to produce an output signal. A second watermark may be embedded into the remainder signal before the final addition step. Further, cryptographic techniques may be used to encrypt the reduced data signals and to encrypt the remainder signals before the final addition step.