US 5,224,162 A · Electronic cash system

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.

Claims11

Dependent claims

An electronic cash system wherein a user who possesses electronic cash and a license issued from a bank uses said electronic cash, including:

Step 1 wherein said user furnishes a shop with information containing a composite number, said electronic cash and said license, said composite number being the product of at least two prime numbers;
Step 2 wherein said shop verifies the validity of said license and said electronic cash and, if they are valid, creates and offers inquiry information to said user;
Step 3 wherein said user calculates, following said inquiry information, a residue power root of a function using said composite number as a modulo and provides it as response information to said shop;
and
Step 4 wherein said shop uses said composite number to verify the validity of said response information.

2 more elements

An electronic cash system wherein a user uses a license and electronic cash issued from a bank, including:

Step 1 wherein said bank establishes a hierarchial structure table which is a tree having a plurality of levels and in which one node corresponding to the face value of said electronic cash issued to said user is set to the highest level and nodes of lower levels are sequentially branched from said node of the highest level in a tree form, and a unit value is made to correspond to each node so that the unit value corresponding to a desired node is equal to the total sum of the unit values of immediately descendant nodes branched therefrom;
Step 2 wherein said user selects a combination of nodes corresponding to the amount of money used from said hierarchial structure table in accordance with the following restrictions:
(a) Once a node is used, all of its ancestor and descendant nodes should not be used thereafter;
and
(b) Each node should not be used more than once;
and
Step 3 wherein said user creates amount of money information corresponding to each of said selected nodes and offers it to said shop together with said electronic cash and said license.

4 more elements

Dependencies are inferred from the claim text.

Electronic cash system

Life of this patent

Electronic cash system

Life of this patent

Abstract

Claims11