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.

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.

Procedure

To validate a signature when opening an file

1. Click Tools menu  Options.At the command prompt, enter options.
2. In the Options dialog box, Open and Save tab, select Display Digital Signature Information.
3. Click OK.
4. Open a signed file.

   In the Digital Signature Contents dialog box, in the Other Fields list, select details of the digital signature, such as the issuer, beginning and expiration dates of the digital ID, and the serial number.

5. Click Close.

To validate a signature using the Validate Digital Signatures icon

1. Open a signed file.
2. On the status bar, click the Validate Digital Signatures icon.
3. In the Validate Digital Signatures dialog box, if the file has a valid digital signature, click View Base Signature.

   The Digital Signature Contents dialog box displays details of the digital signature such as the signer, expiration date of the digital ID, serial number, comments about the digital signature, time stamp, and time service.

4. Click Close.
5. If the file contains an external reference (xref) that contains a digital signature, select View Xref Drawings in the Validate Digital Signatures dialog box. Click View Xref Signature to view the external references associated with the file.
6. Click Close.

To validate a signature in Windows Explorer

1. In Windows Explorer, locate a file whose digital signature you want to check.

   Some operating systems display a modified icon for a drawing that has a valid digital signature attached.

2. Right-click the file name. Click Properties.
3. In the Properties dialog box, if the file contains a digital signature, the Digital Signature tab is displayed. Click the Digital Signatures tab to view the digital signature details.

   A Valid Signature icon is displayed if a digital signature is valid, and an Invalid Signature icon is displayed if the digital signature is not valid.

4. In the Other Fields list, select an option from the list to view details of the digital signature, such as the issuer, description, and expiration date of the digital ID. You can also view the time stamp and time service.
5. When you have finished viewing the digital signature information, click OK.

To identify a signed file in Windows Explorer

• In Windows Explorer, locate files that you want to check for a digital signature. Signed files are displayed with the Digital Signatures icon.

  

To turn on or off the Digital Signatures icon display in Windows Explorer

1. In Windows Explorer, locate a file that has a digital signature icon.
2. Right-click the file name. Click Enable/Disable Digital Signature Icons.
3. Click the check box next to Validate Digital Signatures and Display Special Icons to turn on the icon display in Windows Explorer, or clear the check box to turn off the icon display.
4. Click OK. Log out of Windows, and then log back in.

To prevent signature status from being displayed for valid signatures

1. Click Tools menu  Options.At the command prompt, enter options.
2. In the Options dialog box, Open and Save tab, clear the Display Digital Signature Information option.
3. Click OK.

Quick Reference

Commands

SECURITYOPTIONS

Specifies password or digital signature options for a drawing file.

SIGVALIDATE

Displays information about the digital signature attached to a drawing file.

System Variables

SIGWARN

Controls whether a warning is presented when a file with an attached digital signature is opened.

Utilities

Attach Digital Signatures

Attaches a digital signature to files.