If a signature displays the date and time, that time is the local time on the signer’s computer. However, a second date and time may appear in the Signature Properties dialog box, indicating that the signer uses a timestamp server. To validate a signature that contains a timestamp, you must obtain the certificate for the timestamp server and add it to your list of trusted identities. Otherwise, the timestamp appears in the Signatures panel as unverified, and you must validate the timestamp manually.