Patent ID: 7552335

Claim:
An information processing apparatus for processing original data created by a predetermined author, the apparatus comprising: inputting means for inputting the original data, original-data assuring information for assuring that the original data is an original, a first piece of modification information that indicates how to modify the original data to obtain modified original data, a sequence of (n−1) pieces, up to an nth piece, of modification information, where for (2≦k≦n−1) the kth piece of modification information indicates how to modify the original data already modified in sequence by the first to the (k−1)th piece of modification information, and n pieces of modification-assuring-information for detecting whether corresponding modification information has been altered; original-data verifying means for verifying, by the original-data assuring information, that the original data is assured as being an original; modification-information verifying means for verifying, by the respective pieces of modification-assuring-information, that the respective pieces of modification information regarding a modification of the original data is assured as not having been altered; determination means for determining whether the original data and the respective pieces of modification information have been altered; and modifying means for modifying the original data based on the first to the nth piece of modification information when the determination means determines that none of the first to the nth piece of modification information has been altered, modifying the original data based on the first to the mth piece of modification information when the determination means determines that none of the original data and the first to the mth piece of modification information has been altered and that an (m+1)th piece of modification information has been altered, and not modifying the original data when the determination means determines that either the original data or the first piece of modification information has been altered.