System and method of creating and sending broadcast and multicast data

1. A method of deriving at least one multiparty cryptographic key for use by at least three computing devices and encrypting data transferred between the at least three computing devices, comprising:

receiving, from the first computing device, an authentication packet comprising a first random number encrypted using the secret key for the first computing device and an identification number for the first computing device;

retrieving, from a database, a stored secret key for the first computing device using the device identification number for the first computing device;

decrypting the first random number using the stored secret key;

generating a second random number; and

generating the first base cryptographic key using the first random number and the second random number;

generating a multiparty cryptographic key;

determining a first offset between the multiparty key and the first base cryptographic key;

encrypting the first offset using the first base cryptographic key; and

communicating the encrypted first offset to the first computing device.

2. The method of claim 1 , wherein the step of generating a multiparty cryptographic key comprises:

generating a third random number and a fourth random number; and

generating the multiparty cryptographic key using the third random number and the fourth random number.

3. The method of claim 1 , wherein the step of encrypting the first offset using the first base cryptographic key comprises:

encrypting the first offset and a second random number using a secret key for the first computing device.

4. The method of claim 3 , wherein the step of communicating the encrypted first offset to the first computing device comprises:

transmitting the encrypted first offset and second random number to the first computing device.

5. The method of claim 1 , wherein the secret key for the first computing device is stored in memory.

6. The method of claim 1 , further comprising:

establishing a second base cryptographic key for a second computing device;

determining a second offset between the multiparty cryptographic key and the second base cryptographic key;

encrypting the second offset using the second base cryptographic key; and

transmitting the encrypted second offset to the second computing device.

7. The method of claim 6 , wherein the step of establishing a second base cryptographic key for a second computing device comprises:

retrieving, from a database, a stored secret key for the second computing device using the device identification number for the second computing device;

decrypting the first random number using the stored secret key;

generating a second random number; and

generating the second base cryptographic key using the first random number and the second random number.

8. The method of claim 6 , wherein the step of encrypting the second offset using the second base cryptographic key comprises:

encrypting the second offset using a secret key for the second computing device.

9. The method of claim 1 , further comprising:

using the multiparty cryptographic key to communicate among the at least three computing devices.

10. A method for deriving at least one shared cryptographic key for use by at least three computing devices and encrypting data transferred between the at least three computing devices, comprising:

generating a first random number and encrypting the first random number using a secret key for a first computing device;

sending to a second computing device a first authentication packet, the first authentication packet comprising the encrypted first random number and a device identification number for the first computing device;

receiving, from the second computing device, a packet comprising an encrypted first offset and an encrypted second random number;

decrypting the encrypted first offset and second random number;

determining a first base cryptographic key using the first random number and the second random number;

determining the multiparty cryptographic key using the first base cryptographic key and the first offset;

wherein the first offset is between the multiparty key and the first base cryptographic key.

11. The method of claim 10 , wherein the secret key for the first computing device is stored on a smart card.

12. The method of claim 10 , wherein the secret key for the first computing device is stored on a memory of the first computing device.

13. The method of claim 1 , further comprising using the multiparty cryptographic key to communicate among the at least three computing devices.

14. A method for generating a multiparty cryptographic key, comprising:

a first computing device encrypting a first random number using a secret key for the first computing device;

the first computing device sending to a host a first authentication packet, the first authentication packet comprising the encrypted first random number and an identification number for the first computing device;

a second computing device retrieving a stored secret key for the first computing device using the identification number;

the second computing device using the stored secret key to decrypt the first random number;

the second computing device generating a first base cryptographic key using the first random number and a second random number;

the second computing device generating a multiparty cryptographic key using a third random number and a fourth random number;

the second computing device determining a first offset between the multiparty cryptographic key and the first base cryptographic key;

the second computing device encrypting the first offset and second random number using the stored secret key;

the second computing device transmitting the encrypted first offset and second random number to the first computing device;

the first computing device decrypting the encrypted first offset and second random number;

the first computing device determining a first base cryptographic key using the first random number and the second random number; and

the first computing device determining the multiparty cryptographic key using the first base cryptographic key and the first offset.

15. The method of claim 14 , further comprising:

the first computing device generating an IGMP query;

the first computing device encrypting the IGMP query using the first base cryptographic key;

the first client sending the encrypted IGMP query to the second computing device;

the second computing device decrypting the IGMP query;

the second computing device sending the IGMP query to a third computing device;

the second computing device generating a multiparty cryptographic key using a fifth random number and a sixth random number;

the second computing device linking the multiparty cryptographic key to an multiparty IP address;

the second computing device determining a second offset between the multiparty cryptographic key and the first base cryptographic key;

the second computing device encrypting the second offset and the multiparty

IP address using the first base cryptographic key;

the second computing device transmitting the encrypted second offset and the multiparty IP address; and

the first second computing device determining the multiparty cryptographic key using the first base cryptographic key and the second offset.