User guide

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Digital signature timestamp
Digital timestamps mark a PDF signature with the time and date as proof of integrity. A timestamp shows
that the contents of the document existed at a point in time, and are unchanged.
For added security, digital signatures can include a timestamp from an independent, trusted authority.
Nitro Pro 9 is able to utilize a timestamp server to help ensure that the timestamp is precise and secure,
since the system clock could be modified by a user.
To manage digital timestamp settings:
1. In the File menu, select Preferences, expand Digital Signature, and select Time Stamp Servers
2. If the list of Available servers is empty, or you want to add another timestamp server:
a. Click New to add a new timestamp server. The Time Stamp Server dialog appears.
b. Enter the name and URL of a timestamp server, and optional login information
c. Click OK to save your settings
3. To manage existing settings for a timestamp server, tick the Acquire timestamp from attestable
server checkbox, select a timestamp server from the list of Available servers, and then do any of
the following:
o
To update properties for the selected timestamp server, click Edit, and enter new
information on the Time Stamp Server dialog
o
To remove the selected timestamp server, click Delete
o
To use a specified timestamp server by default for every timestamp, click Set Default. A star
marks the default timestamp server.
4. Click OK
TIP: If your default timestamp server is unavailable, Nitro Pro 9 uses the first available timestamp server
on your list. You are advised to list them in order of preference.
When you look at the properties of a digital signature, time validity is shown as one of the following:
l Signature date/time are from the clock on the signer's computer
l Signature is timestamped but the timestamp could not be verified
l Signature is timestamped
For more information, see Digital signatures.
Nitro Pro 9 - User Guide