The clean room technique is a process in which a new product is developed by reverse engineering an existing product, and then the new product is designed in such a way that patent or copyright infringement is avoided. The clean room technique is also known as clean room design. (Sometimes the words "clean room" are merged into the single word, "cleanroom.") Sometimes this process is called the Chinese wall method, because the intent is to place a demonstrable intellectual barrier between the reverse engineering process and the development of the new product.
The use of the clean room technique can be compared, in some respects, with the fair use of copyrighted publications in order to compile a new document. For example, a new book about Linux can be authored on the basis of information obtained by researching existing books, articles, white papers, and Web sites. This does not necessarily constitute copyright infringement, even though other books on Linux already exist, and even if the new book contains essentially the same information as the existing publications. However, this is the case only as long as passages from the existing works are not copied verbatim or nearly verbatim, and as long as the new work does not have substantially the same structure as any of the existing works.
Use of the clean room technique puts engineers and enterprises in a legal gray area. If the owner of the original copyright or patent can demonstrate that the development of a new product was done by means of reverse engineering and is not significantly different from the existing product, a lawsuit may result. Any attempt to reverse engineer an existing product, and then create a new product based on the results of the reverse engineering process, should be undertaken only with the advice of a reputable attorney who is experienced in copyright infringement and reverse engineering issues.