Patent ID: 7310735

Claim:
A method for distributing computer software from a first computer system, comprising the first computer system performing: maintaining keys of computer systems authorized to access software to be distributed; receiving a request for software from a second computer system; generating a message; encrypting the generated message; transmitting the encrypted message to the second computer system; receiving an encrypted response from the second computer system; determining whether there is one maintained key for the second computer system capable of decrypting the received encrypted response; decrypting the encrypted response with the determined key if there is one determined key; determining whether the decrypted response includes a part of the generated message transmitted to the second computer system, with wherein the second computer system is authorized to access the software if the decrypted response includes the part of the generated message and wherein the second computer system is not authorized to access the software if there is not one maintained key for the second computer system that is capable of decrypting the encrypted response or the decrypted response does not include the part of the generated message transmitted to the second computer system; and permitting the second computer system access to the software after determining that the second computer system is authorized to access the software.