To enable the user of an electronic computer to store data or to transmit data through a communication means represented by the Internet or the like to another personal computer with high confidentiality and high safety.

A computer program stored in a personal computer P1 for storage/transmission is provided to separate/divide "division origin data" into "division primary data" and "division secondary data" by bit units, and to store or transmit those data. In this case, different separation/division methods are applied by each selling unit to allow only a software product by the same selling units to prepare data having the same bit string as that of the "division origin data" from the "division primary data" and "division secondary data". Thus, it is possible to increase confidentiality and safety.