Cryptographic communication system

A cryptographic communication system including at least one of first type terminals using a first cipher type, at least one of second type terminals using a second cipher type different from the first cipher type, and n cryptographic protocol conversion servers (n.gtoreq.2) using the first and second cipher types, said first type terminals, said second type terminals and said cryptographic protocol conversion servers being connected to one another through at least one of networks;

• wherein
• said first type terminal includes:
• dividing means for dividing data to be transmitted to a terminal of said second type terminals into k items of data to be distributed among k cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of said n cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of said second type terminals,
• encryption means for encrypting the k items of data generated by said dividing means according to the first cipher type,
• transmitting means for adding terminal information representing each of said first type terminals and said second type terminals to each of said k items of data encrypted by said encryption means, and then transmitting said k items of data encrypted to said k cryptographic protocol conversion servers respectively, via said at least one of networks,
• decryption means for decrypting the k items of data transmitted from each of said k cryptographic protocol conversion servers according to the first cipher type, and
• restoring means for restoring original data from the k items of data decrypted by said decryption means;
• said second type terminal includes:
• dividing means for dividing data to be transmitted to a terminal of said first type terminals into k items of data to be shared among k cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of said n cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of said first type terminals,
• encryption means for encrypting the k items of data generated by said sharing means according to the second cipher type,
• transmitting means for adding terminal information representing each of said second type terminals and said second type terminals to each of said k items of data encrypted by said encryption means, and then transmitting said k items of data encrypted to said k cryptographic protocol conversion servers respectively, via said at least one of networks
• decryption means for decrypting the k items of data transmitted from each of said k cryptographic protocol conversion servers according to the second cipher type, and
• restoring means for restoring original data from the k items of data decrypted by said decryption means;
• and
• each of the n cryptographic protocol conversion servers includes:
• cipher conversion means for decrypting one data item transmitted from any one of said first type terminals and said second type terminals according to the cipher type of the first and second cipher types which is used by a transmission terminal indicated by the terminal information added to the data, and then re-encrypting the data according to the cipher type of the first and second cipher types which is used by a reception terminal indicated by the terminal information added to the data, and
• transmitting means for transmitting one data item re-encrypted by said cipher conversion means to the reception terminal indicated by the terminal information added to the data.

A cryptographic communication system including at least one of first type terminals using a first cipher type, at least one of second type terminals using a second cipher type different from the first cipher type, n first type cryptographic protocol conversion servers (n.gtoreq.2) using a third cipher type which is different from the first and second cipher types, and n second type cryptographic protocol conversion servers (n.gtoreq.2) which use the second and third cipher types and each of which beforehand corresponds to each of the n first type cryptographic protocol servers, said first and second type terminals and said first and second type cryptographic protocol conversion servers being connected to one another through at least one of networks;

• wherein
• each of said first type terminals includes:
• dividing means for dividing data to be transmitted into k items of data to be distributed among any of k independent cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of the n first type cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of the second type terminals,
• encryption means for encrypting the k items of data generated by said dividing means according to the first cipher type,
• transmitting means for adding terminal information representing a transmission terminal and a reception terminal to the k items of data encrypted by said encryption means, and then transmitting said k items of data encrypted to the k first type cryptographic protocol conversion servers,
• decryption means for decrypting the k items of data transmitted from each of said k first type cryptographic protocol conversion servers according to the first cipher type, and
• restoring means for restoring original data from the k items of data decrypted by said decryption means;
• each of said second type terminals includes:
• dividing means for dividing data to be transmitted into k items of data to be distributed among any of k independent cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of said n second type cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of said first type terminals,
• encryption means for encrypting the k items of data generated by said dividing means according to said second cipher type,
• transmitting means for adding terminal information representing a transmission terminal and a reception terminal to the k items of data encrypted by said encryption means, and then transmitting said k items of data encrypted to said k second type cryptographic protocol conversion servers,
• decryption means for decrypting the k items of data transmitted from each of said k second type cryptographic protocol conversion servers according to the second cipher type, and
• restoring means for restoring original data from the k items of data decrypted by the decryption means;
• each of said n first type cryptographic protocol conversion servers includes:
• cipher conversion means for decrypting one data item transmitted from any one of said first type terminals according to the first cipher type and then re-encrypting the data according to the third cipher type and for decrypting one data item transmitted. from a corresponding one cryptographic protocol conversion server of said n second type cryptographic protocol conversion servers according to the third cipher type and then re-encrypting the data according to the first cipher type, and
• transmitting means for transmitting one data item re-encrypted according to the third cipher type by said cipher conversion means to a corresponding one cryptographic protocol conversion server of said n second type cryptographic protocol conversion servers and for transmitting one data item re-encrypted according to the first cipher type by said cipher conversion means to a reception terminal indicated by the terminal information added to the data;
• and
• each of said n second type cryptographic protocol conversion servers includes:
• cipher conversion means for decrypting one data item transmitted from any one of the second type terminals according to the second cipher type and then re-encrypting the data according to the third cipher type and for decrypting one data item transmitted from a corresponding one cryptographic protocol conversion server of said n first type cryptographic protocol conversion servers according to the third cipher type and then re-encrypting the data according to the second cipher type, and
• transmitting means for transmitting one data item re-encrypted according to the third cipher type by said cipher conversion means to corresponding one cryptographic protocol conversion server of said n first type cryptographic protocol conversion servers and for transmitting one data item re-encrypted according to the second cipher type by said cipher conversion means to a reception terminal indicated by the terminal information added to the data.

An information processing device for use in a cryptographic communication system including at least one of first type terminals using a first cipher type, at least one of second type terminals using a second cipher type different from the first cipher type, and n cryptographic protocol conversion servers (n.gtoreq.2) each of which uses the first cipher type and the second cipher type and converts data encrypted according to one cipher type to data encrypted according to the other cipher type, said first type terminals, said second type terminals and said third type terminals being connected to one another through at least one of networks, said information processing device being used as each of said first type terminals, characterized by comprising:

• dividing means for dividing data to be transmitted into k items of data to be distributed among any of k independent cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of said n cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of said second type terminals;
• encryption means for encrypting the k items of data generated by said dividing means according to the first cipher type;
• transmitting means for adding terminal information representing a transmission terminal and a reception terminal to the k items of data. encrypted by said encryption means, and then transmitting said k items of data encrypted to said k cryptographic protocol conversion servers;
• decryption means for decrypting the k items of data transmitted from each of said k cryptographic protocol conversion servers according to the first cipher type;
• and
• restoring means for restoring original data from the k items of data decrypted by said decryption means.

A cryptographic communication method for use in a cryptographic communication system including at least one of first type terminals using a first cipher type, at least one of second type terminals using a second cipher type different from the first cipher type, and n cryptographic protocol conversion servers (n.gtoreq.2) using the first and second cipher types, said first type terminals, said second type terminals and said cryptographic protocol conversion servers being connected to one another through at least one of networks, said cryptographic communication method performing cryptographic communication between the first type terminals and the second type terminals, characterized in that:

• each of said first type terminals divides data to be transmitted to a terminal of said second type terminals into k items of data to be distributed to k cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of said n cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of the second type terminals, encrypts the divided k items of data according to the first cipher type, and adds terminal information representing a transmission terminal and a reception terminal to the encrypted k items of data to transmit the data to the k cryptographic protocol conversion servers;
• each of the n cryptographic protocol conversion servers decrypts one data item transmitted from any terminal of the first type terminals according to the first cipher type, re-encrypts the decrypted data according to the second cipher type, and transmits the re-encrypted one data item to a reception terminal which is indicated by the terminal information added to the data;
• and
• each of the second type terminals decrypts the k items of data transmitted from each of the k cryptographic protocol conversion servers according to the second cipher type, and restores original data from the decrypted k items of data.

A cryptographic communication method for use in a cryptographic communication system including at least one of first type terminals using a first cipher type, at least one of second type terminals using a second cipher type different from the first cipher type, and n cryptographic protocol conversion servers (n.gtoreq.2) using the first and second cipher types, the first type terminals, the second type terminals and the cryptographic protocol conversion servers being connected to one another through at least one of networks, said cryptographic communication method performing cryptographic communication between the first type terminals and the second type terminals, characterized in that:

• each of the first type terminals divides data to be transmitted into k items of data to be distributed among k cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of the n cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of the second type terminals, encrypts the divided k items of data according to the first cipher type, and then adds terminal information representing a transmission terminal and a reception terminal to the encrypted k items of data to transmit the data to the k cryptographic protocol conversion servers, and also decrypts the k items of data transmitted from each of the k cryptographic protocol conversion servers according to the first cipher type, and then restores original data from the decrypted k items of data;
• each of the second type terminals divides data to be transmitted into k items of data to be distributed among k cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of the n cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of the first type terminals, encrypts the divided k items of data according to the second cipher type, adds terminal information representing a transmission terminal and a reception terminal to the encrypted k items of data to transmit the data to the k cryptographic protocol conversion servers, decrypts the k items of data transmitted from each of the k cryptographic protocol conversion servers, according to the second cipher type, and restore original data from the k items of data decrypted by said decryption means;
• and
• each of the n cryptographic protocol conversion servers decrypts one data item transmitted from any one of the first type terminals and the second type terminals according to the cipher type of the first and second cipher types which is used by a transmission terminal indicated by the terminal information added to the data, then re-encrypts the data according to the cipher type of the first and second cipher types which is used by a reception terminal indicated by the terminal information added to the data, and transmits the re-encrypted one data item to the reception terminal indicated by the terminal information added to the data.

A cryptographic communication method for use in a cryptographic communication system including at least one of first type terminals using a first cipher type, at least one of second type terminals using a second cipher type different from the first cipher type, n first type cryptographic protocol conversion servers (n.gtoreq.2) using a third cipher type which is different from the first and second cipher types, and n second type cryptographic protocol conversion servers (n.gtoreq.2) which use the second and third cipher types and each of which beforehand corresponds to each of the n first type cryptographic protocol servers, the first and second type terminals and the first and second type cryptographic protocol conversion servers being connected to one another through at least one of networks, said cryptographic communication method performing cryptographic communication between the first type terminals and the second type terminals, characterized in that:

• each of the first type terminals divides data to be transmitted into k items of data to be distributed among k cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of the n first type cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of the second type terminals, encrypts the divided k items of data according to the first cipher type, adds terminal information representing a transmission terminal and a reception terminal to the encrypted k items of data to transmit the data to the k first type cryptographic protocol conversion servers, decrypts the k items of data transmitted from each of the k first type cryptographic protocol conversion servers according to the first cipher type, and restores original data from the decrypted k items of data;
• each of the second type terminals divides data to be transmitted into k items of data to be distributed among k cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of the n second type cryptographic protocol conversion servers on the basis of the data to be transmitted to a terminal of the first type terminals, encrypts the divided k items of data according to the second cipher type, adds terminal information representing a transmission terminal and a reception terminal to the encrypted k items of data to transmit the data to the k second type cryptographic protocol conversion servers, decrypts the k items of data transmitted from each of the k second type cryptographic protocol conversion servers according to the second cipher type, and restores original data from the decrypted k items of data;
• each of the n first type cryptographic protocol conversion servers decrypts one data item transmitted from any one of the first type terminals according to the first cipher type and then re-encrypts the data according to the third cipher type and for decrypting one data item transmitted from corresponding one cryptographic protocol conversion server of the n second type cryptographic protocol conversion servers according to the third cipher type and then re-encrypting the data according to the first cipher type, and transmits one data item re-encrypted according to the third cipher type to corresponding one cryptographic protocol conversion server of the n second type cryptographic protocol conversion servers and for transmitting one data item re-encrypted according to the first cipher type to a reception terminal indicated by the terminal information added to the data;
• and each of the n second type cryptographic protocol conversion servers decrypts one data item transmitted from any one of the second type terminals according to the second cipher type and then re-encrypts the data according to the third cipher type and for decrypting one data item transmitted from corresponding one cryptographic protocol conversion server of the n first type cryptographic protocol conversion servers according to the third cipher type and then re-encrypting the data according to the second cipher type, and transmits one data item re-encrypted according to the third cipher type to corresponding one cryptographic protocol conversion server of the n first type cryptographic protocol conversion servers and for transmitting one data item re-encrypted according to the second cipher type to a reception terminal indicated by the terminal information added to the data.

An information processing method for a cryptographic communication system including at least one of first type terminals using a first cipher type, at least one of second type terminals using a second cipher type different from the first cipher type, and n cryptographic protocol conversion servers (n.gtoreq.2) using the first and second cipher types, said first type terminals, said second type terminals and said cryptographic protocol conversion servers being connected to one another through at least one of networks, said cryptographic communication method performing cryptographic communication between the first type terminals and the second type terminals, characterized in that:

• k items of data to be distributed among k cryptographic protocol conversion servers (n.gtoreq.k.gtoreq.2) of the n cryptographic protocol conversion servers are divided on the basis of the data to be transmitted to a terminal of the second type terminals, the divided k items of data are encrypted according to the first cipher type, terminal information representing a transmission terminal and a reception terminal is added to the encrypted k items of data to transmit the data to the k cryptographic protocol conversion servers, k items of data transmitted from the k cryptographic protocol conversion servers are decrypted according to the first cipher type, and then original data are restored from the decrypted k items of data.