| 摘要 |
An extraction section (102) extracts user identification information and communication terminal identification information from electronic mails acquired by an acquisition section (101). Then, a calculation section (103) calculates a uniqueness number of the communication terminal identification information for each of the extracted user identification information. Then, a verification section (104) judges whether the uniqueness number of communication terminal identification information for each of the calculated user identification information has exceeded a predetermined threshold. Then, for each case, a notification section (105) performs predetermined notification to a notification destination set up in advance. |
