A recording medium storing a program for causing a computer to execute processing including: creating first and second partial certificate information from certificate information that includes attribute information of a signer and certification information used to certify the attribute information, based on a data amount of an electronic document, in response to a signing request for the electronic document; generating an electronic signature for the electronic document and the first partial certificate information; attaching the generated electronic signature to the electronic document and the first partial certificate information, and transmitting the electronic document and the first partial certificate information with the electronic signature attached to a submission source of the electronic document; and transmitting the second partial certificate information to a verification device that verifies authenticity of the certificate information, using another route different from a route that connects the submission source and a submission destination of the electronic document.