For more information:

Frequently-asked Questions from Architects and Engineers

White Paper: 
Digital Signatures for Architects' and Engineers' Drawings

Summary of Licensing Board Regulations

Information for Reprographers

Free Handwriting Fonts

Is it legal to sign architectural and engineering documents using the Banjo plug-in?

Each jurisdiction has its own requirements, so before applying a digital signature to permitting documents an architect or engineer should check with the applicable licensing board to verify that this is legal.  See the Summary of Licensing Board Regulations for more information.

The Banjo plug-in complies with the requirements of many licensing boards regarding digital signatures.  In particular, it meets the National Council of Examiners for Engineering and Surveying (NCEES) guidelines which state that the signature must be:

• Unique to the person using it

• Capable of verification 

• Under the sole control of the person using it

• Linked to a document in such a manner that the digital signature is invalidated if any data in the document is changed

If I put my seal and signature on a PDF, doesn't that make it easy for someone to copy and misuse them?

It all depends on how your seal and signature are applied to the PDF.  If you were to scan in your signature and apply it as a "stamp" to the PDF, or if you import a scan of your signature as a bitmap image in CAD software, then you are creating an unsecure situation.  Anyone could change the original document, or could copy your seal and signature out of your document and put it on a different document, and there would be no way to tell that this had happened or prove that you were not responsible for this action.

When you use the Banjo plug-in, however, the process is secured on several levels.  Because the Banjo plug-in creates true digital signatures (not just scans of handwritten signatures) the image of your signature is a dynamic entity that reflects the integrity of the document.  If a change is made to a signed document, the signature appearance will instantly change to indicate that the signature is no longer valid.  

And when you choose digital signatures as your method of signing documents, you are establishing a defensible standard for your practice.  If you always use digital signatures to sign electronic documents (rather than a simple stamp or bitmap image) then you will have a basis for proving the authenticity (or lack of authenticity) of any document that may be attributed to you.  

For example, if someone were to scan in your seal and signature from a set of paper documents and place this scan on a new, forged document, you could prove that the document did not originate in your office.  This new document would not have a true digital signature, and because all your electronic documents are digitally signed, it could not have originated from your office.

Is it possible for someone forge a digital signature?

Given enough time and expertise, anything is possible.  Doing so would be extremely difficult, however, as digital signatures use highly secure and well-tested encryption mechanisms.

Someone could purchase the Banjo plug-in, create a forged seal and handwritten signature, and use these to create a digital signature that has the appearance of a legitimate digital signature from a licensed architect or engineer.  If this were to happen, though, the forgery could be easily exposed.  Every digital signature is intrinsically associated with a digital certificate (or digital ID) which links the signature to a specific individual.  The digital certificate used to create a false digital signature would be different from the one that the licensed professional uses, and the two could be compared to prove that the false documents were not signed by the professional.

In this way, digital signatures provide a greater level of security than handwritten signatures, because with a handwritten signature there is often no way to prove conclusively who signed a document.  

If I send a digitally signed document to someone, can they re-use my seal and signature on a different document?

No.  Your digital signature is "locked" onto the PDF that you signed, and it cannot be extracted and re-used.  

It is possible, through a variety of means, to extract the image of your seal and signature from a digitally signed document, and these could possibly be used for unauthorized purposes.  This would be similar to someone taking a set of printed plans from a job site, scanning in the seal and signature (or just cutting and pasting the paper) and using these on a different set of documents.  This would not be a true digital signature, however -- it would just be a scan or bitmap image of a seal and signature.

In this situation, the digital signature provides a greater level of security than the traditional paper-based system, because the digitally-signed PDF archived at the professional's office is the ultimate proof of what is a legitimate document and what is not.  A forged document can be easily exposed as fraudulent when an office has standardized on digital signatures.

Some vendors of computer-aided design (CAD) software sell digital signature products as well.  What is the difference between those and the Banjo plug-in?

Digital signature products that work with CAD software (such as the AutoCAD Digital Signature Extension and MicroStation Digital Security) use a similar means (digital signatures) for a different purpose.  

A digital signature is only useful to secure the document to which it is attached.  If you plan to send CAD files (such as .DWG or .DGN files) to other people, and you want to ensure that no unauthorized changes are made to these files, then one of these CAD-based products is the correct solution.  

If, however, you don't want to send your CAD files but would rather send a PDF (because it can be more accurately printed, or because it safeguards your design data) then the Banjo plug-in will meet your needs.  

This is because the digital signature only works on the signed file.  If you digitally sign a CAD file and then create a PDF or plot file from that CAD file, the digital signature does not "carry over" to the PDF.  The security features of the digital signature remain with the CAD file, but the PDF would be unsecured.  

So if you plan to send PDFs to clients, to a printing service, or to another office, the Banjo plug-in will provide the security for these documents that a CAD-based solution cannot.

I send my drawings out to a reprographer to be plotted.  Will they be able to print PDFs with digital signatures?

Your reprographer will need to install either the free Banjo Verify plug-in or the low-cost Banjo Verify plug-in with Batch Print in order to verify your digital signature and print your drawings.  Please refer your them to the Information for Reprographers page for more information.

A digitally-signed PDF can be printed without using one of these plug-ins, but your signature will display as "Unverified" as a warning that it could not be validated.

How can I find out more?

The best way is to download a free trial and start working.  The free trial version is fully functional, and will allow you to evaluate the software for three days.  Click here to go to the download page.

The "help" file will be loaded when you install the plug-in, but it is also available on-line.  Click here to read the help documentation.

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