Drawing files with digital signatures provide the following benefits:

• Recipients of drawings are provided with reliable information about who created a
  drawing.
• Owners of drawings are provided with reliable verification that a drawing has not
  been modified since it was digitally signed.

To attach a digital signature to a file, you must either have a digital certificate
issued by a certificate authority, or you can create a self-signed certificate using
one of several utilities.

You can examine a file’s digital signature. This is important when you are working
on collaborative projects, or if you receive an executable file. For drawing files,
an icon is displayed on the status bar if a drawing file is digitally signed.

When you click the icon, you can verify information such as the validity of the signature,
the name of the individual or organization that signed the file, and so on.

Supported Data File Types

You can attach a digital signature to the following file types with the DIGITALSIGN
command:

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

Invalid Digital Signatures

A digital signature will become invalid for the following reasons:

• The file was modified after the digital signature was attached.
• The file was corrupted in transit or when the digital signature was attached.
• The digital certificate was revoked by the certificate authority.

Reapply a Digital Signature to a Drawing

In some cases, you might need to make changes to a drawing file and then reapply your
digital signature. In those cases, use WBLOCK, specifying the entire drawing, and
save it to a different file name for the sake of version control. Then apply your
digital signature.