Differential Data Creating System, Data Updating System, And Differential Data Creating Method

The purpose of the present invention is to provide a technology capable of enhancing the effect of reducing the size of differential data. A bit shift unit 4a shifts either old data or new data by each of 0, 1, 2,... and n bits in the forward direction and the backward direction of a bit string thereof, thereby creating a plurality of data. A copy bit string extracting unit 4b extracts copy bit string information on the basis of the plurality of data and other data not shifted. An additional bit string extracting unit 4c extracts additional bit string information obtained by excluding the copy bit string from the new data. A differential data creating unit 6 creates differential data on the basis of the copy bit string information and the additional bit string information. 本发明的目的在于提供种能够提高差分数据的数据量削减效果的技术。比特移位部(4a)将旧数据和新数据中的方数据向其比特串的正向及逆向分别移动0，1，2，...，n比特，从而生成多个数据。复制比特串提取部(4b)基于多个数据和未被移位的另方数据，提取复制比特串信息。追加比特串提取部(4c)从新数据提取去除复制比特串后的追加比特串信息。差分数据生成部(6)基于复制比特串信息和追加比特串信息，生成差分数据。