Signatures in AutoCAD 2011

[cheryla]

I am trying to find a better way to sign architectural drawings in AutoCAD. Right now we print our sheets to PDF, and use a separate program to sign the PDFs. We have considered creating a signature and putting it on a hidden layer, but when we share CAD drawings with consultants, they would have access to the signature, so that's not secure enough. Any other suggestions?

[cadtag]

What are the legal requirements or architects in Wyoming, (and any other jurisdictions you deal with)? That't the first question.

If they allow digital signatures, you can do that within AutoCAD. see "Overview of Digital Signatures" in Help. You'll need a digital ID from a public key vendor, but the software will help walk you through that

if you are talkling about something else, e.g. a scanned version of a wet ink signature, then i'll just say 'Don't"

[cheryla]

Thank you for your help. I think instead of going with a digital signature, we will just place an image of the wet signature on our CAD drawings right before we print to PDF, then erase it from the drawing so no one has access to it.

[cadtag]

I guess I'm going to ask "Why bother?" That scenario provides 0 protection for a picture of the signature getting out into the wild (it would take all of 1 second to capture that image from the PDF and save it somewhere for nefarious use).

Secondly, I seriously doubt if any court would consider that equivalent to a wet-ink signature, and instead would have no alternative to considering the drawings sent out that way as simply unsigned.

And thirdly, have you in fact verified that the wyoming architectural board will permit that? Can any of the agencies you submit to for permits legally accept that as a signed drawing? (Whether they do at the moment is immaterial -- the question is can they do so legally? or would any building permits obtained with a 'picture of a signature' be potentially invalid? ) Will clients refuse to pay bills because your group did not fulfill their legal requirements for obtaining permits?

[BeKirra]

If I fully understand what you said, this is your situation:
You have to share (or submit or whatever) you cad drawings with signature,
but you don't want any of the receivers to take or to modify your signature. right?

It just like that you hand money to someone but don't want them to touch with finger print or use it.
Unfortunately it is impossible!
Unless you accept an image of signature of any kind.

[arshiel88]

Acrobat Professional have the ability to put their own digital/wet signature and protect the document with read-only access. It can even restrict printing and copying content if you want. But I haven't saw a program who can prevent the user pressing PrintScreen(PrtScn) to capture your wet ink signature. I guess digital signature is the way to go.

[Norton_cad]

What about RTEXT? You could add a RTEXT string that calls up the last save or plot. That way any edit that dosn't match your origional date is an invalid copy.

[dgorsman]

What about RTEXT? You could add a RTEXT string that calls up the last save or plot. That way any edit that dosn't match your origional date is an invalid copy.

Until somebody diddles the file contents to plain text to match the original. The issue is not just providing the signature, but securely ensuring the file has not been modified since the signature was applied. In the future there may be better file protection schemes, but for now the best cover-yer-assets path is to deal with the hand cramps.

Copies of wet ink signatures are generally a bad idea. When we provide CAD drawings that have been issued, they are sent without stamps or signatures. Issued copies are printed with the engineers stamp, who then sign that print. We retain those wet-ink signed hard copies for archive purposes.

[tedg]

Until somebody diddles the file contents to plain text to match the original. The issue is not just providing the signature, but securely ensuring the file has not been modified since the signature was applied. In the future there may be better file protection schemes, but for now the best cover-yer-assets path is to deal with the hand cramps.

Copies of wet ink signatures are generally a bad idea. When we provide CAD drawings that have been issued, they are sent without stamps or signatures. Issued copies are printed with the engineers stamp, who then sign that print. We retain those wet-ink signed hard copies for archive purposes.
I agree with all that's been said and I know there are tons of threads that discuss this.
We do the image of the wet-stamp thing too (when the receiving state allows it versus embossed stamps or "originals" etc). But we keep the image on the local drive so no one else with access to the server wouldn't accidently e-transmit it out with the file. We NEVER send out a cad file with a stamp or signature.

Assuming you're sending PDF's as your deliverables;

What is the difference between placing an image of a stamp and signature in a cad file, creating a PDF from AutoCAD... versus signing and stamping one copy, then scanning it to PDF?

You still have a PDF that someone can digitally steal the stamp, the first scenareo you just don't have a master wet stamped sheet, which usually doesn't leave the office anyway, and you've taken out one step which makes a better PDF?

We live in a digital age now, I would expect some type of security software for this type of thing to get invented in our future. It will just take one good law suit to get it started.

[jaberwok]

There are also questions of legal validity - and they started the day the fax machine was invented. :(

[cadtag]

We live in a digital age now, I would expect some type of security software for this type of thing to get invented in our future. It will just take one good law suit to get it started.


Already done. it's called a digital signature, and is based on public key infratructure, It works reasonably well (unless you're CIA or NSA..) , and will stand up in court.

[tedg]

Already done. it's called a digital signature, and is based on public key infratructure, It works reasonably well (unless you're CIA or NSA..) , and will stand up in court.
Really? Cool.
How does it work, do you load a document file (PDF or DOC etc) into it and add a signature? Or does it kick out a proprietary type of digital document that you need the software to read?

[cadtag]

from Help....


Specifically, digital signatures provide the following benefits:

Recipients of digitally signed files can be sure that the organizations or individuals who sent the files are who they claim to be.
A digital signature guarantees that a file has not changed since the file was signed.
A signed file cannot be rejected as invalid. The signer of a file cannot disown the file later by claiming the signature was forged.
A digital signature is not the same as a digitized signature. While a digital signature helps prove your identity and a drawing's authenticity, a digitized signature is nothing more than an electronic version of your own signature. It can be forged and copied, and has no real security value.

Digital IDs use two keys—a public key, which anyone can use to validate a digital signature, and a private key, which is known only by the originator of the digital ID. The private key is used to create the digital signature. To learn more about digital IDs, digital signatures, and public and private keys, search the Internet for these terms.

You can attach signatures to files that are compatible with AutoCAD 2000 and later file formats, including files generated by the eTransmit feature. To attach a signature to multiple files at once, or to attach a signature to a file compatible with the AutoCAD 2000 or later drawing-file format, see Attach Digital Signatures Dialog Box in the Command Reference.

Essentially you purchase a 'digtal ID from a PKI vendor, (verisign, tharpe, etc) and use that to sign the files. any bytes get changed in the file, and the signature is invalid. which proves that the file has been altered from the exact state it was in when it was signed.