Electronic cash system

US5224162A · kind A · utility

Assignee

• NIPPON TELEGRAPH AND TELEPHONE CORPORATION · JP

Inventors

• Tatsuaki Okamoto · Musashino, JP
• Kazuo Ohta · Zushi, JP

Key dates

• Filing date: Jun 8, 1992
• Grant date: Jun 29, 1993
• Expiry date: Jun 8, 2012

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L2209/56
• WIPO field: IT methods for management
• WIPO sector: Electrical engineering

Abstract

In an electronic cash system, K sets of blind signature information are derived from secret information containing identification information of a user, K/2 sets of them are opened and a bank attaches a blind signature to the remaining K/2 sets of information. The user obtains a signed license from the blind signature. The user generates blind signature information from the license and a desired amount of money and gets a blind signature of the bank to the blind signature information and obtains electronic cash signed by the bank from the blind signature. The user presents to a shop a residue power root of a node in a money hierarchial structure and the electronic cash, corresponding to the amount of money to be used, and the shop verifies their validity and, if they are valid, offers inquiry information to the user. The user offers, as response information, a residue power root of the node corresponding to the amount of money to be used to the shop. The shop verifies the validity of the response information and, if it is valid, acknowledges the payment with electronic cash of the amount of money to be used.