Patent ID: 8205075

Claim:
A non-transitory, computer readable recording medium having stored thereon data to be communicated in a communication, comprising: at least one data structure having at least the following distinct areas: a data area for containing digital information that is a substantial object of the communication; a header area attached to the data area at a head of the data to be communicated; a header authentication data area for containing header authentication data used for authentication of the header area, the header authentication data area is created based on data comprised in the header area and a first algorithm with which a first algorithm operation is performed on the data within the header area; and an authentication data area for containing authentication data used for authentication of the data area and the header authentication data area, the authentication data area is created by performing a second algorithm operation on data contained in the data area and the header authentication data area, wherein the header area contains a second algorithm information for identifying a second algorithm which is different from the first algorithm and is used to authenticate the data area using the authentication data.