What is the Adobe® Acrobat Time Stamp Server support?
An example PDF file that you can download to view and verify on your computer with Adobe Reader. Summary: The content of this PDF file has been notarized by DigiStamp via an electronic time stamp. This is evidence that this content
and your signature existed at a point-in-time. You can view this evidence
using Adobe Reader on your computer. This file's content cannot be altered
without the tampering being detected by the Acrobat Reader software.
Starting with Acrobat version 7, the Acrobat products include support for
time stamping your digital signature. The Acrobat products with time stamp
support are Professional, Standard and Reader (with Reader Extensions enabled
files) The purpose of time stamping a digital signature was defined in
the digital signature standards. In summary, when a time stamp is added
to your signature then you have an external witness to when you signed
the document (more information is here).
The process of adding a time stamp to your signature
does not send your document outside your computer.
Time stamping does not compromise the privacy of
your document - only a "SHA-1" hash of
the signature is sent to DigiStamp to create the
time stamp (more information is here).
Adobe provides instructions about how to configure timestamps in Adobe
Reader 8 at this link (alternatively, this link). Or, we provide instructions below.
Here is an example of the
signature properties when a trusted time stamp is
included:
For further information on
the Acrobat products contact Adobe Systems (http://www.Adobe.com).
Setup Acrobat to
use the time stamp servers from DigiStamp
Configure Acrobat to use time
stamp servers (the screens may vary in appearance
depending of the version of Acrobat that you use):
Specify the DigiStamp servers:
Primary server: http://tsa1.digistamp.com/TSA
Backup server if the
primary is unavailable: http://tsa2.digistamp.com/TSA
The beginning text "http://" is required, or Acrobat will later
respond with:
"Unsupported transport protocol"
If Acrobat responds with error: "Transport authorization failure"
then:
- your account number is not correct (even a space at the end causes this)
- the password is entered wrong
- or your account has no balance
If Acrobat responds with error: "Error encountered while BER decoding"
or
"Unspecified transport error" then check that the server URL
above is entered
correctly as: http://tsa1.digistamp.com/tsa
Setup Acrobat to
verify the authenticity of the time stamps
At this point in the setup
process we encourage you to create a signature.
View the signature properties (right click on the
signature and select "Properties"). Two
images are given below. Depending on the results,
you may need to continue with designating your trust
of the DigiStamp public key certificate. There is
background information about DigiStamp public key
certificates here.
There are two approaches for accepting the DigiStamp
public key:
1.
The preferred method
is importing the DigiStamp CA certificate
into the Acrobat key store. This method is
explained by clicking here.
2.
A quick method for
verifying just this one time stamp is explained
by clicking here.
This image below is an example
of when you need to take another step to accept
the DigiStamp public key certificate:
