Disclosed is an apparatus for forming an arcuate channel in one or more segments of a bone, bony structure or adjacent vertebrae of a spine. The assembly may be attached, adhered, or otherwise embedded into or upon a removable oral appliance to form a bearing aid assembly. A CPU extracts certification information encrypted by a secret key of a user of the sending side and decrypts the certification information by use of a public key. It is checked whether the input image data is used to print a text image or a graphichalftone image.