| 摘要 |
A document secure against tampering or alteration and method and apparatus for producing and authenticating such a document. A document is scanned to produce a digital signal which is compressed, encrypted, and coded as a two dimensional barcode or as some other appropriate form of coding, which is incorporated into a label which is the affixed to the document. In one embodiment the signal representing the image is encrypted using a public key encryption system and the key is downloaded from a center. This key maybe changed from time to time to increase security. To facilitate authentication the corresponding decryption key is encrypted with another key and incorporated on the card. To validate the document the coded signal is scanned from the label, decoded, decrypted, expanded and displayed. The card may then be authenticated by comparison of the displayed representation of the image and the document.
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