2011

NOTE If you want to retain valid digital signature status, do not add a password
or otherwise modify or save a file that already has a digital signature attached.
Make modifications, such as adding passwords, before signing the file. Signature
information does not remain intact if you modify, save, or export drawing data.
View Digital Signature Details
When you receive a file that contains a digital signature, you can check
whether the file was modified since it was signed, and other information.
An icon is displayed in the status bar when a file contains digital signature
information. When you click the icon, you can verify the following
information:
■ Validity of the file
■ Whether the file was modified since it was signed
■ Individual or organization that signed the file
■ Time stamp and comments attached to the file
■ Issuer (certificate authority) of the digital ID
■ “Valid to” and “valid from” dates for the digital ID
Digital signatures work on files that are compatible with AutoCAD 2000 and
later drawing-file formats. If you receive a signed file and save the file, it is
considered modified, and the signature is invalidated. However, you generally
can still view information about it. If you receive a signed drawing-file and
save the file, the signature information can be lost.
NOTE If the SIGWARN system variable is on and you open a file with a valid
signature, the digital signature status is displayed. If SIGWARN is off and you open
a file, the digital signature status is displayed only if a signature is invalid.
You can also view the properties of a drawing file in Windows Explorer to
examine and validate a digital signature. Some operating systems display a
modified icon for a drawing that has a valid digital signature attached. If the
modified icon is displayed, your computer may slow down (depending on
processor speed and file size), so you can turn off the display.
To validate a signature when opening an file
1 Click Tools menu ➤ Options.
1938 | Chapter 40 Protect and Sign Drawings