Importance

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Abstract

In a portable electronic device, a method of authenticating a document associated with a geographical location is disclosed. A document is provided in the form of digital data, and a hash value is generated from the digital data of said document. Raw GPS data are received from at least one GPS satellite, and then digitally signed by a first private key of the portable electronic device. From the raw GPS data, exact GPS coordinates are calculated. A request for an authentic location stamp is sent to a certification unit, the request containing at least the hash value of the document, the raw GPS data and the exact GPS coordinates, wherein said request is digitally signed by a private key of the portable electronic device. In response to said location stamp request, a nonce value from the certification unit is received, said nonce value being digitally signed by a private key of the certification unit. A certification request is then sent to the certification unit, said request containing at least the hash value of the document, the raw GPS data, the exact GPS coordinates and the nonce value, wherein the certification request is digitally signed with said private key of the portable electronic device. In response to said certification request, a certified location stamp containing said certification request and a piece of time information is received, said location stamp being digitally signed by a private key of the certification unit. The certified location stamp is verified by using the corresponding public key of the certification unit, and if it is determined that the certified location stamp is signed by the certification unit, the certified location stamp will be assigned to the document.

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First Claim