An information processing system including an image inputting apparatus and an information processing apparatus, wherein the image inputting apparatus comprises a first certification control unit that sends a certification request, in which a public key certificate is designated, to a certification apparatus connected with the image inputting apparatus through a network and receives proof data indicating that certification is completed from the certification apparatus, a delegating unit that sends the proof data to the information processing apparatus, which is connected with the image inputting apparatus through the network, and a sending unit that sends a delivery request for delivering image data input by the image inputting apparatus to the information processing apparatus, wherein the information processing apparatus is configured to acquire an access right to a delivery destination of the image data using the proof data sent by the delegating unit, wherein the public key certificate is stored on a card and read by a card reader connected to or built in the image inputting apparatus, wherein the first certification control unit receives the proof data, which indicates that the certification is completed and is encrypted by the certification apparatus, and a first session key used for communication between the image inputting apparatus and the certification apparatus from the certification apparatus, the delegating unit receives a second session key, which is used for communication between the image inputting apparatus and the information processing apparatus and encrypted by the first session key from the certification apparatus, the delegating unit sends the proof data by sending the second session key decrypted by the received first session key, the proof data, and the first session key encrypted by the decrypted second session key to the information processing apparatus, and the information processing apparatus acquires the access right to the delivery destination of the image data from the certification apparatus using the first session key decrypted by the decrypted second session key and the sent proof data. wherein the image inputting apparatus comprises a first certification control unit that sends a certification request, in which a public key certificate is designated, to a certification apparatus connected with the image inputting apparatus through a network and receives proof data indicating that certification is completed from the certification apparatus, a delegating unit that sends the proof data to the information processing apparatus, which is connected with the image inputting apparatus through the network, and a sending unit that sends a delivery request for delivering image data input by the image inputting apparatus to the information processing apparatus, wherein the information processing apparatus is configured to acquire an access right to a delivery destination of the image data using the proof data sent by the delegating unit, wherein the public key certificate is stored on a card and read by a card reader connected to or built in the image inputting apparatus, wherein the first certification control unit receives the proof data, which indicates that the certification is completed and is encrypted by the certification apparatus, and a first session key used for communication between the image inputting apparatus and the certification apparatus from the certification apparatus, the delegating unit receives a second session key, which is used for communication between the image inputting apparatus and the information processing apparatus and encrypted by the first session key from the certification apparatus, the delegating unit sends the proof data by sending the second session key decrypted by the received first session key, the proof data, and the first session key encrypted by the decrypted second session key to the information processing apparatus, and the information processing apparatus acquires the access right to the delivery destination of the image data from the certification apparatus using the first session key decrypted by the decrypted second session key and the sent proof data.