In a target apparatus which stores at least one piece of domain key information in a first area and a plurality of pieces of content key information each associated with any one of the domain key information in a second area, a method for generating data for detecting tampering of the content key information. The method comprises the steps of encrypting the content key information associated with one of the domain key information using a chain encryption technique, extracting data at predetermined positions in the encrypted content key information, concatenating the pieces of data extracted at the predetermined positions in the encrypted content key information to obtain concatenated data, performing a hash calculation with respect to the concatenated data to obtain a hash value, storing check values corresponding to the data at the predetermined positions in plain text, in the target apparatus, and storing the hash value in the target apparatus.