| 摘要 |
PROBLEM TO BE SOLVED: To detect the alteration of a portion that has been already received in a step in which a portion of an electronic file is receive and also to decide whether or not the entire electronic file is received. SOLUTION: A transmission source divides an original electronic file into file configuration units X(1) to X(N). Then, record units 240, etc., are produced in the following way, and the record units 240 are sequentially transmitted. In the production of a record unit, a descriptor H for checking the completeness of file units, an identifier F for checking whether or not the file units are the first part or the last part of an electronic file, and a descriptor C' for checking the completeness (meaning that preceding and subsequent file units are not omitted) of the consecutive relation of the file units are attached to the respective file units X. |
