Patent ID: 7756270

Claim:
An apparatus for enciphering data comprising: a cipher producing portion for subjecting input data to enciphering process in accordance with rules determined by key data to produce cipher data; an enciphering portion for subjecting digital information data to enciphering process responding to one of random number data and pseudo-random number data produced on the basis of the cipher data obtained from the cipher producing portion to produce enciphered digital information data; a data supplying portion for producing the input data for the cipher producing portion with initial value data supplied thereto and supplying the cipher producing portion with the produced input data; and an initial value data supplying portion for supplying initial value data which vary at each data partition of the digital information data supplied to the enciphering portion to the data supplying portion, wherein the initial value data include both of line number data which vary at each line of the digital information data and frame number data which vary at each frame of the digital information data, and wherein the random number data and pseudo-random number data produced on the basis of the cipher data are different for each data partition of the digital information data.