Patent ID: 8351610
Filing Date: 2013-01-08
Classification: H04L

Abstract:
1. A communication system including a first communication apparatus and a second communication apparatus as two communication apparatuses capable of encrypting transmission subject data in plain text to render it as encrypted data and then transmitting it to the communication apparatus at the other end and also decrypting received encrypted data and rendering it as the transmission subject data, wherein: both the first communication apparatus and the second communication apparatus comprise: cutting means for cutting the transmission subject data by a predetermined number of bits into multiple pieces of transmission subject cut data, and also cutting the encrypted data by the same number of bits by which the encrypted data is cut when encrypted into multiple pieces of encrypted cut data; algorithm generating means for sequentially generating algorithms rendered common between the first communication apparatus and the second communication apparatus; encrypting and decrypting means for encrypting the transmission subject cut data with the algorithm and a predetermined key to render it as the encrypted data and decrypting the encrypted cut data with the algorithm used when encrypting the encrypted cut data and the same key as the key to render it as the transmission subject cut data; connecting means for connecting the decrypted transmission subject cut data to render it as the transmission subject data; and transmitting and receiving means for transmitting and receiving the encrypted data, and the algorithm generating means generates the algorithm each time the transmission subject data is encrypted or the encrypted data is decrypted, and uses a predetermined solution obtained by assigning at least one of past solutions to a solution generating algorithm in the case of generating the algorithm and also erases the past solutions when it is no longer necessary to assign them anew.