Patent ID: 8832202

Claim:
A non-transitory computer-readable recording medium storing an E-mail information management program for causing a computer, which manages E-mail information, to execute a process comprising: acquiring a plurality of predetermined information from a mail header and a mail body, and acquiring, as signature related information, information relating to said plurality of predetermined information, network information of the computer, and a time stamp for signature information, thereby acquiring, as signature target information, said acquired information with attributes thereof made corresponding to respective first attribute tags; producing feature variable information for said signature target information acquired, and acquiring said feature variable information in a corresponding relation to second attribute tags indicating said feature variable information; producing a hash value from an entirety of both said signature target information acquired and said feature variable information produced, producing electronic signature data using a secret key of the computer and said hash value, and acquiring said electronic signature data in a corresponding relation to a third attribute tag indicating said electronic signature data; determining whether or not to produce a fourth attribute tag including an exact copy of said mail body based on whether a size of said mail body exceeds a maximum size threshold specified by policy information; storing, as signature header information, said signature target information acquired, said feature variable information produced, and said electronic signature data produced in a header portion of E-mail in a corresponding relation to said associated attribute tags; storing the fourth attribute tag in said header portion of E-mail when the fourth attribute tag including the exact copy of said mail body is produced based on said determining indicating that the size of said mail body does not exceed said maximum size threshold specified by said policy information; comparing, for each said attribute tag, the stored signature header information with candidate signature information included in the mail header; and determining whether each attribute of the email has been altered based on a result of said comparing.