1. Before using Outlook Express for query service, you must first finish settings of the directory service server. For detail settings, refer to this section on “How to Set Outlook Express Directory Service”.
2. Open Outlook Express, click “Directory” and open directory service.
3. Enter “Directory” and click “Search for People” to enter your search for natural persons.
4. Under “Query (K)”, click “moica.nat.gov.tw” and fill in names of natural persons you want to search under “Name (N)”. Click “Immediate Search” to start searching and then click the search results. You will be able to view information after clicking “Contents.” (You can also use “Advanced” search method to search people you want by entering more conditions for searching).
5. In the natural persons contents menu, click “Contents” to the left to view the searched contents. Then, click “Digital Identification Code” to view natural persons certificates information. Clicking “Export” you will save information of this Citizen Digital Certificate.

Setting procedures are as follows:

1. Open “Outlook Express” and click “Tools/Accuont.”
2. And click “To Add/Directory Service” to the right.
3. Enter “moica.nat.gov.tw” to “Internet Directory Server” field, then click “Next” to complete this adding to the directory server.
4. Open “Outlook Express,” click “Tools/Account/All” in the account name list. Click this “moica.nat.gov.tw” directory service, then click “Contents.”
5. Click “Contents”, then click “Advanced”. Fill in “c=TW” under “Basis for Search”, and click “Confirm” to end. You can then check natural persons certificates from Outlook Express.

LDAP Query Service is a software directory access protocol which enable one to look up organizations, individuals, files, devices and other resources. It stores a citizenDN and certificate to permit others check Citizen Digital Certificate with this protocol.