US006718314B2United States Patent (10) Patent N0.: (45) Date of Patent:

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Date: 2015-05-26 20:08:36 Payment systems Financial cryptography David Chaum Credit card Patent examiner Patent application Patent Economy		US006718314B2United States Patent (10) Patent N0.: (45) Date of Patent: Add to Reading List Source URL: www.chaum.com Download Document from Source Website File Size: 4,12 MB Share Document on Facebook