Adobe 22002486 Digital Signature User Guide - Page 111
What is a timestamp?, How Do I Validate a Timestamp in a Signature?
View all Adobe 22002486 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 111 highlights
Acrobat 9 Family of Products Security Feature User Guide Validating Signatures Validating Signature Timestamps 111 What is a timestamp? A timestamp is like a signature inside of a signature. Like signatures, timestamps are provided by someone (a timestamp authority) who uses a certificate to confirm their identity. A timestamp's certificate must be valid (not revoked by the issuer) and trusted (by you) for the timestamp to be valid. Timestamp certificate status appears in the Date/Time and Summary tabs of the Signature Property dialog: Untrusted timestamp certificates appear as follows: Figure 79 Timestamps: Untrusted stamp Trusted timestamps that have been added to the Trusted Identities list and have been explicitly trusted for signing appear as follows: Figure 80 Timestamps: Trusted stamp How Do I Validate a Timestamp in a Signature? Validating a timestamp is the process by which you check to see if the timestamp was applied and that its certificate is valid. In order to validate a timestamp, you need to manually verify: The timestamp was applied: If a timestamp fails for some reason (the server cannot be found, the network is down, etc.), timestamping fails silently. The timestamp certificate is trusted: If a timestamp was applied, the certificate must be trusted by adding to your trusted identities list. To verify that a signature has been properly timestamped: 1. Display the Signature Properties dialog by right clicking on any signature in the document or the Signatures tab and choosing Show Signature Properties. 2. Choose the Date/Time tab. Timestamp status is indicated by the icon and associated text: Warning triangle: Timestamping failed or a timestamp is not present and the local time is used. Verify the signer used a timestamp. Magnifying glass: A timestamp may have been used but you have not yet trusted the timestamp certificate. Proceed to the next step. Clock: A timestamp with a trusted certificate was used. Figure 81 Timestamps: Date/Time tab