An authentication server connected via a network to a communication client that generates a bit signal by capturing an image of a self-aware two-dimensional code generated from an original two-dimensional code, the self-aware two-dimensional code being provided with an information area (Cd) that expresses designated information with a cell distribution pattern, and a correction area (Ce) that is constituted by a plurality of symbols and expresses correction information for correcting errors with a cell distribution pattern, wherein the self-aware two-dimensional code is generated by: acquiring a first correction bit sequence (1, li) from one part of the correction area (Ce) of the original two-dimensional code, the first correction bit sequence (1, li) comprising symbols that belong to the plurality of symbols and that are included in the one part of the correction area (Ce), and acquiring a second correction bit sequence (m, mi) from a part different from the one part of the correction area (Ce), the second correction bit sequence (m, mi) comprising symbols that belonging to the plurality of symbols and that are included in the part different from the one part of the correction area (Ce); calculating the exclusive OR of the first correction bit sequence (1, li) and the second correction bit sequence (m, mi); and substituting the one part of the correction area (Ce) with a bit sequence indicating the exclusive OR, and the authentication server comprising: bit signal receiving means that receives the bit signal transmitted from the communication client via the network; decoding means that decodes the bit signal received by the bit signal receiving means to acquire the designated information and the correction information; error detecting means that uses the correction information acquired by the decoding means to detect the exclusive OR of the first correction bit sequence (1, li) and the second correction bit sequence (m, mi) as error, the exclusive OR of the first correction bit sequence (1, li) and the second correction bit sequence (m, mi) being embedded into the correction area (Ce); two-dimensional code authenticating means that authenticates the self-aware two-dimensional code by determining whether or not the exclusive OR (m') of the first correction bit sequence (1, li) included in the correction information and the error detected by the error detecting means matches the second correction bit sequence (m, mi) included in the correction information; and information transmitting means that, when the two-dimensional code authenticating means obtains an authentication result of both matching, transmits the designated information acquired by the decoding means to the communication client via the network. acquiring a first correction bit sequence (1, li) from one part of the correction area (Ce) of the original two-dimensional code, the first correction bit sequence (1, li) comprising symbols that belong to the plurality of symbols and that are included in the one part of the correction area (Ce), and acquiring a second correction bit sequence (m, mi) from a part different from the one part of the correction area (Ce), the second correction bit sequence (m, mi) comprising symbols that belonging to the plurality of symbols and that are included in the part different from the one part of the correction area (Ce); calculating the exclusive OR of the first correction bit sequence (1, li) and the second correction bit sequence (m, mi); and substituting the one part of the correction area (Ce) with a bit sequence indicating the exclusive OR, and bit signal receiving means that receives the bit signal transmitted from the communication client via the network; decoding means that decodes the bit signal received by the bit signal receiving means to acquire the designated information and the correction information; error detecting means that uses the correction information acquired by the decoding means to detect the exclusive OR of the first correction bit sequence (1, li) and the second correction bit sequence (m, mi) as error, the exclusive OR of the first correction bit sequence (1, li) and the second correction bit sequence (m, mi) being embedded into the correction area (Ce); two-dimensional code authenticating means that authenticates the self-aware two-dimensional code by determining whether or not the exclusive OR (m') of the first correction bit sequence (1, li) included in the correction information and the error detected by the error detecting means matches the second correction bit sequence (m, mi) included in the correction information; and information transmitting means that, when the two-dimensional code authenticating means obtains an authentication result of both matching, transmits the designated information acquired by the decoding means to the communication client via the network.