Patent ID: 7765582

Claim:
A method for using identity-based encryption (IBE) to securely convey messages in a system in which individuals who are senders communicate with individuals who are recipients over a communications network, wherein the recipients each have an associated message address and each have an IBE public key that is based on the message address and an associated IBE private key, wherein the system includes a plurality of IBE private key generators each of which generates a plurality of associated IBE private keys for a plurality of associated recipients to use in decrypting messages encrypted with their respective IBE public keys, wherein each IBE private key generator generates different IBE public parameter information to be used in encrypting messages for its associated recipients, wherein the different IBE public parameter information generated by each IBE private key generator is maintained by a different respective IBE public parameter hosting service, and wherein each IBE public parameter hosting service has a different service name that is used to communicate with that hosting service over the network, the method comprising: with computing equipment at a sender who desires to send an encrypted message to a given recipient who is associated with a given one of the IBE private key generators, generating the service name of the IBE public parameter hosting service that maintains the IBE public parameter information for the given IBE private key generator using the IBE public key of the given recipient; with the computing equipment, sending a request for the IBE public parameter information to the IBE public parameter hosting service that maintains the IBE public parameter information for the given IBE private key generator by providing servers in the communications network with information on the service name; with the computing equipment at the sender, obtaining the requested IBE public parameter information over the communications network from the IBE public parameter hosting service; and with the computing equipment at the sender, encrypting a message for the given recipient using the obtained IBE public parameter information and the IBE public key of the given recipient.