Patent ID: 8832448

Claim:
A dual-channel electronic signature system, comprising: a signature verification server; a signature requester device for calculating a characteristic value related to content of a target document, encoding the characteristic value, a destination message and at least a portion of content of the target document to generate a first graph, and outputting the first graph, wherein the destination message is utilized for combining with a predetermined string to form a destination network address pointed to the signature verification server; and a hand-held device for capturing and decoding an image of the first graph to obtain the characteristic value and the destination message, performing an electronic signature operation on the characteristic value to generate a signature data, encoding the signature data and a hardware identification code to generate a second graph, combining the destination message with the predetermined string to generate the destination network address, and transmitting the second graph to a destination network address, wherein the predetermined string is pre-stored in the hand-held device, related to a network address of the signature verification server, and not allowed to be changed by a user of the hand-held device; wherein if the signature data contained in the second graph passes a verification procedure of the signature verification server, the signature verification server transmits a verification graph corresponding to the second graph to the signature requester device.