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The Digital Signature Extension is useful for anyone who shares design data electronically with others. Digital signatures reduce your risk as the sender of a drawing, because any modification to the drawing after it has been sent out invalidates your signature. If you’re a drawing recipient, digital signatures assure you of the identity of the signer and provide nonrepudiation, so the signer cannot disown the drawing, claiming never to have signed it.

2. Does this extension work with industry-specific products based on the AutoCAD® platform?

Yes. The Digital Signature Extension signs and validates files from those applications as well as Autodesk® Map, Autodesk® Land Desktop, and AutoCAD® Mechanical software.

3. Does this extension work on AutoCAD LT?

No. The Digital Signatures Extension does not work on AutoCAD LT® software.

4. Does this extension require a service pack?

No. This extension does not require any special service pack for any of your Autodesk products in order to operate.

5. What is the difference between an electronic signature and a digital signature?

An electronic signature (as defined by the Electronic Signature in Global and National Commerce Act), is “electronic sound, symbol, or process, attached to or logically associated with a contract or other record and executed or adopted by a person with the intent to sign the record.” This could be the signer’s name, spelled out in ASCII characters at the bottom of a e-mail message, or a recorded mouse click on an “I Agree” button on a web page. Attorneys and legislators, however, prefer to reserve the term “digital signature” for applications that use public encryption keys and matching private encryption keys to transmit documents securely and to “sign” them. The broader term “electronic signature” includes this more restricted class of “digital” signatures as well as other kinds of electronic signatures that do not use public key encryption.

6. What is the underlying technology of the Digital Signature Extension?

The Digital Signature Extension is based on public key cryptography, a well known and established technology standard.

7. Can I actually see the signer’s handwritten signature?

No. While the signer may embed a digitized version of a hand signature in the drawing for clarification purposes, the actual “digital signature” is a unique, mathematical property of the file, displayable through a software interface.

8. Can I sign multiple drawings at once?

Yes, the Digital Signature Extension allows users to sign multiple files in a single session.

9. Can a digital signature be forged?

For all practical purposes, no. The cryptography algorithms used by the Digital Signature Extension can be considered to be very secure. A fraudulent signature is much more likely to be the result of a stolen computer or a signer’s compromised password than a crack of the cryptography code.

10. Are digital signatures legally enforceable?

In the United States, the Electronic Signature in Global and National Commerce Act or “E-SIGN” law essentially states that a contract cannot be negated simply because it was agreed to electronically. Many states now have or are considering much more detailed legislation that spells out what technology is acceptable, for instance. You should contact your local government to find out more information.

11. What is a digital ID or digital certificate?

A digital ID, or digital certificate, is an electronic document that acts as an online passport by uniquely identifying the holder. The digital signature includes a copy of the signer’s ID, so the recipient of a signed document is assured of the identity of the signer.

12. How do I get a digital ID?

Digital IDs can be obtained from a commercial certificate authority. For more information on how to obtain a digital ID, and recommended vendors, please visit Autodesk® Point A.

13. Can I use my digital ID with other applications such as Microsoft Outlook?

Most applications, including the Digital Signature Extension and Microsoft® Outlook, support the X.509 digital certificate standard. That means you can use a single digital ID to sign design documents with the Digital Signature Extension and e-mail messages with Outlook.

14. What happens if someone changes a digitally signed file?

Any changes to the file that are saved back to disk invalidate the signature.

15. What is the Digital Signature Verifier?

The Digital Signature Verifier is a free application that verifies signatures on signed DWG and eTransmit files on computers that do not have the Digital Signature Extension installed.

16. Can I open a digitally signed DWG file in an older version of AutoCAD software?

Yes. If you have the Digital Signature Verifier installed you are able to view the signature and are warned that any edits to the file will invalidate the signature.

17. Can I use digital signatures to prevent unauthorized people from viewing my files?

Digital signatures provide security in the following three areas:

Identity—As a drawing recipient, I can be sure that the person or corporation that sent me the drawing is who they claim to be.
Data Integrity—I can be sure that the drawing has not changed in any way, either intentionally or accidentally, since it was signed.
Nonrepudiation—The signed drawing cannot be repudiated. The signer of the drawing cannot later disown it, claiming the signature was forged.

Digital signatures do not prevent data from being copied, and cannot be considered a prevention against intellectual property theft.