Is there a CAD program that ...............

I send a lot of digital files around for various reasons (To Designers, other Surveyors etc) and I always keep a copy of the, date stamped, file that I sent on for this very reason. If you were really worried you could burn it to a read only media as well (CD) again with a copy for yourself to use as proof in the future if required.

Where possible I also send it via email, as I keep records of the emails etc as well. Where it's too large and has to go on a USB, I still send an email saying what files are on the USB etc.

Can't you lock them like Acrobat/pdf files?
I know with those you can lock for read-only.
Or password protect them for edits - if you so desire.

Your AutoCAD installation should include a utility program for attaching digital signatures to drawings. From the ACad help files:

With a digital signature, you can collaborate more easily with others on projects. 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.

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.
NoteOnce 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.

From the AutoCAD help files

LOCKING DRAWING FILES

When I send a drawing to someone and I don't want it to be tampered with, I use the following procedure:
1. Start a new drawing.
2. Enter MINSERT on the command line.
3. When prompted for the name, enter the full path of the drawing to protect.
4. For the insertion point, enter 0,0.
5. Enter 1 for the X & Y factor.
6. Rotation angle = 0.
7. Number of rows = 2.
8. Number of columns = 1.
9. Distance between rows = 0.
The drawing cannot be exploded or revised. ....

Note in CAD: "This drawing will self destruct in 5 seconds".

Mission Impossible

Thank you all.

SWMBO will be 'having a go' and will report back to y'all.

BTW, it's not that I'm paranoid (totally anywho) it's just that I don't like persons to be mislead, particularly as I cannot be "there" to see what they are reading/using and to let them know that WYSINWYG.

Cheers,

Derek

PS-

As we can see, this Board has the depth of international knowledge.

Let's let more of our colleagues know about it please.

Thank you Angel and Wendell

Derek before I retired from teaching last spring I added an assignment on digital signatures and Ohio law and administrative rules for their use. The Ohio law follows U.S. law which in turn complies with international standards. I will forward the assignment and answer sheet with the hope that it will provide additional food for thought. I would suggest you look at an article "Electronic Information Transfer Requirements" prepared for Ohio Surveying News in 2009.

Thank you Dallas for the leads and your E-mail too.

Did you look at the case cited ?

Our professional body should have been there and Grammelhofer sentenced to rock splitting for a few years !

It was very disappointing to Mr. Mitche.

Cheers

Derek

> Thank you Dallas for the leads and your E-mail too.
>
> Did you look at the case cited ?
>
> Our professional body should have been there and Grammelhofer sentenced to rock splitting for a few years !
>
> It was very disappointing to Mr. Mitche.
>
> Cheers
>
> Derek

Yes I reviewed the cited case. I would think Mr. Mitche and/or your professional licensing authority would also have cause for legal action. Altering the document over his certification may be considered forgery as well as fraudulent. Altering a drawing for submission to a government body could also be construed as surveying without a license. Likely the statue of limitations on both of these has run out. Also the satisfaction of seeing the defendants hauled through additional legal proceedings would likely not be worth the cost and time required.