公开(公告)号：AT370479T

公开(公告)日：2007-09-15

申请号：AT03799521

申请日：2003-12-19

Applicant: IBM

Inventor： LOTSPIECH JEFFREY ,  SRINIVASAN SAVITHA ,  SIGFREDO NIN ,  DALIT NAOR ,  RAM REDDY ,  BLAKELEY BURNETTE

IPC: G07F19/00 ,  G06Q20/00 ,  G07F7/00 ,  H04L9/00 ,  H04L29/06

Abstract: A system, method, business method, and computer program product for conducting electronic transactions with a potentially untrusted server while maintaining user anonymity and transaction privacy, yet allowing the server to verify the user is a valid subscriber entitled to participate in the transaction. Anonymous service requests are sent to the server. The server transmits responses that have been encrypted such that only valid subscribers can decrypt them. Broadcast encryption schemes that enable selective revocation of misbehaving subscribers will tip off requestors that the server is trying to identify them. Transaction and content quantity can be monitored for usage-based billing while maintaining anonymity. Each content item may be uniquely encrypted with a content key that is then encrypted by a session key and included in encrypted form with a response, to reduce the computational workload.