Blind source separation is a promising technique for signal processing

which has such features as blind information processing and waveform restoral. In order to keep the data secret reliably

the applicable principle of BSS in noise removal was extended to form a kind of new method for data secrecy based on the strategy of complete covering

by the introduction of virtual observation. This new method is not only feasible

but of very high security. The results of experiments verified that this new method for data secrecy was simple and effective and had many charming features. For example

it was very simple to use

and has considerable flexibility to implement. Therefore

this method can be used for keeping secrecy of many kinds of different data such as text

speech and image. All of these implied its great potential in information security field.