DATA TRANSMISSION METHOD, DATA TRANSMITTER, PROGRAM RECORDING TRANSMISSION MEDIUM, DATA RECEPTION METHOD, DATA RECEIVER, DATA TRANSMISSION/RECEPTION METHOD AND DATA TRANSMITTER-RECEIVER

摘要

PROBLEM TO BE SOLVED: To prevent the sentences and data of important secrets from being decoded even when plane sentences and cipher sentences are tapped. SOLUTION: An identifier discrimination circuit 11 judges whether or not the identifier of '>' or the like included in a document (plane sentence M) prepared by a user is present, supplies the document and the data or the like indicated by the identifier to a first ciphering circuit 12 when the identifier is present and supplies the document other than the one indicated by the identifier to a second ciphering circuit 13. The first ciphering circuit 12 ciphers the document corresponding to prescribed algorithm and supplies it to a transmission circuit 14 and the second ciphering circuit 13 ciphers the document or the like and supplies it to the transmission circuit 14. The transmission circuit 14 modulates the ciphered data and transmits them through an internet to another mail server.