US Patent 8448719 Key exchange device

The present invention includes a section (102) for generating a plurality of contributing random numbers using a random number, a section (110) for generating a plurality of contributing data using a plurality of contributing random numbers, a section (103) for selecting a number designating contributing data, a section (104) for generating a commitment of the number, a section (126) for saving a contributing random number of the number and disclosure information of the commitment, a section (125) for sending the plurality of contributing data and the commitment, section (134) for generating auxiliary data using a contributing data set and the contributing random number, wherein the auxiliary data and the disclosure information of the commitment are sent from the section (125), and a section (139) for generating a shared key using the contributing data set, the disclosure information of the commitment, the auxiliary data, and the contributing random number.