US 6,061,789 AGranted

Secure anonymous information exchange in a network

AssigneeInternational Business Machines Corporation

InventorsRalf Ch. Hauser, Gene Tsudik

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Abstract

Computer network management for electronic commerce requires technical implementations of business processes. The process addressed here is a technical method for a communication in which two or more parties legitimately want to communicate anonymously, often before discussing a deal or closing a business, e.g. for anonymous bidding or auctioning in electronic commerce. Essentially, the invention is a method, described by a protocol, for safely exchanging data in a network that provides a public key infrastructure and an anonymous communication possibility between network users. It consists of a sequence of steps in which both sender (e.g. customer) and addressee (e.g. merchant) compose data sets (i.e., requests and replies) that are based on received data and/or prior knowledge. The data sets are enciphered to provide anonymity, and digitally signed to provide proof of the partner. The invention is also a system designed to implement the invented method.

Claims13

Dependent claims

A method for anonymous, provable information exchange between a sender and an addressee in a computer network, the computer network providing

a public key infrastructure, preferably with certification, and
an anonymous communication channel available between network users, said method comprising the following steps:
said sender C composes an offer request REQ with a subject or merchandise description MD and a digital signature SIG-c of C,
REQ=(MD,SIG-c),
said REQ is transmitted via said anonymous communication channel to at least one addressee M,
said addressee M composes a reply REP with an offer description OD and its digital signature SIG-m, said digital signature SIG-m being computed over a selection of quantities comprising at least one of MD, OD, SIG-c,
REP=(OD, SIG-m),
and further including M's public key PK-m or public key certificate Cert-m,
said sender C, upon receiving said reply REP, uses M's public key PK-m, known, transmitted, or extracted from said public key certificate Cert-m, to encrypt said received SIG-m, thus determining a first temporary value TMP-1,
TMP-1=PK-m(SIG-m),
said sender C computes a concatenation of said selection of quantities on which said signature SIG-m is based, thus determining a second temporary value TMP-2
TMP-2=H(SIG-c/MD/OD),
said sender C compares said temporary values TMP-1 and TMP-2, a match indicating genuineness of said offer.

10 more elements

Dependencies are inferred from the claim text.