About Digital Signatures

A digital signature identifies an individual or an organization through a digital ID (certificate), and enables you to validate the file. This is especially important when you are working on collaborative projects or transmitting files over the Internet. Recipients of drawings are provided with reliable information about who created a set of drawings and whether they were modified since they were digitally signed. You can validate a digital signature in either the program or Windows Explorer.

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

Note: To attach a digital signature to a file, you must have a digital ID (certificate), which is issued by a certificate authority. A digital ID identifies either an individual or an organization.

Supported File Types

You can attach digital signatures only to files that are compatible with AutoCAD 2000 and later file formats. You can attach signatures to the following file types:

• EXE and ZIP files generated by eTransmit
• DWG and DWT files that are compatible with AutoCAD 2000 and later drawing-file formats
• DWS files (not available in AutoCAD LT)

When you attach a digital signature to a set of files, you can select the files individually from within the signing utility or drag them into the utility from Windows Explorer.

A digital signature is determined to be invalid for the following reasons:

• The file was corrupted when the digital signature was attached.
• The file was corrupted in transit.
• The digital ID is no longer valid.

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.

Tip: Once you attach a digital signature to a drawing file, it will either be valid or invalid. You cannot remove the digital signature from the drawing file. If a digital signature was attached to a drawing in error, save the drawing in DXF format, open the DXF file, and then save it in DWG format.