A scrambling system includes a scrambling apparatus and a descrambling apparatus for scrambling and descrambling digital audio codes having plural sub-band units. Each sub-band unit includes at least a scale factor and a quantized sample data which is quantized after scaling with the scale factor. In the scrambling apparatus, a sample period during which the quantized sample data is present is detected, and only the quantized sample data is scrambled at the sample period. In particular, the quantized sample data and data other than the quantized sample data are separated, and the separated quantized sample data is applied to a scrambler, and the other data is applied to a delay circuit. The separated and scrambled quantized sample data and the delayed data are synthesized. The descrambling apparatus also detects a sample period during which the quantized sample data is present, and descrambles only the scrambled quantized sample data at the sample period.