Patent ID: 7076662
Filing Date: 2006-07-11
Classification: G06F,G11B

Abstract:
1. Data reproducing apparatus for reproducing data recorded as files in at least one directory on a recording medium, comprising: first arithmetic operating means for performing a first predetermined arithmetic operation on each file read from said recording medium, using inputted information serving as a key peculiar to that file, to form a first arithmetic operation value for that file; second arithmetic operating means for performing a second predetermined arithmetic operation on each directory in which at least one of said files is bound, using the first arithmetic operation values of all of the files included in that directory, to form a second arithmetic operation value for that directory; reading means for reading from said recording medium a file and a third arithmetic operation value corresponding to said second arithmetic operation value, said third arithmetic operation value being recorded in a predetermined area of said recording medium; and comparing means for comparing said third arithmetic operation value and said second arithmetic operation value to detect data alteration.