. Another feature of the electronic watermarking method of the invention, is that a validity of an electronic watermark is verified. Another feature of the electronic watermarking method of the invention, is that a validity of an electronic watermark is verified repetitively. According to another aspect of the invention, an electronic watermarking method is provided in which a validity of electronic watermark information of a user embedded through an electronic watermarking process is guaranteed through an encryption process, wherein the 