digital signature

huangyhg

digital signature
does anyone know anything about digital signatures?  texas does not allow a scanned image of a signed seal, but it will allow a digital signature that will be removed if the electronic file is altered.  the last set of drawings i issued, i had them printed out, then i signed them, and then scanned them back to pdf.  the quality of the drawings wasn't that good due to the scanning.  not to mention much more work was involved.  can anyone help?
if you do want to put a seal w/ signature on autocad, just click insert then pick ole object, then pick from file.  first you need to scan your seal and signature and save it as jpeg.  insert that ole object on your title block.  i am also interested w/ digital signature.  we just tried one last week.  sometimes we need to send a drawing somewhere immediately.  it will be nice if we can just send the file to a kinkos somewhere and print them out there (signed).
some states allow you to scan in a signed copy of your seal, but texas specifically says not to do that (i called them to make sure).  i am looking into adding a signature in adobe, but i am not sure how it is going to turn out or how reliable it is going to be.  the basic idea is that if the pdf is modified, then the signature will disappear.  you also are the only one who will be able to add your signature.  if i can get this to work, i will do this for all states, even those that don't require it.  i don't like the idea of my signed seal floating around in autocad.
adobe seems to be the only program that can make this work.  any suggestions?
there is a place on adobe to add a custom stamp.  i bet you can add a scanned image of your seal and signature.  if you want it to disappear if modified then i dont know.
btw, what i meant by sending the stamped file to kinkos was sending it as plot file or pdf.  so the signed seal wont be floating around in autocad.  
maybe we are not talking about the same thing.  the way i have seen it done before is to attach a signed copy of a seal in autocad, then make a pdf.  inevitably, the file gets updated and printed later, and there is the same seal on it again.  i think that is what this board rule is trying to head off.
the scanned image in adobe might work.  i am going to work on it.
ohio does not allow scanned signatures on seals either.  they are working on developing a method to encrypt the digital seal with signature, such that if the original document were altered, the seal will be deleted automatically.  let us know if pdf drawings have that capabiity.      
i just emailed the texas board with my best stab at it.  i will see what they say.
a scanned image of your signature and seal is not an electronic signature.  an electronic signature is a unique encryption algorithm that protects the entire document under its placement.  for instance, if you prepare an adobe pdf file and sign it digitally, you have created a means by which a change in the file by someone else will cause the signature to be void and it will not verify.
many states allow electronic signatures, but only if they comply with accepted encryption techniques that allow the signer (and others) to know if (a) the document is the original; and (b) if it has been changed or modified since it was digitally signed.
all,
see the banjo plug-in for adobe acrobat
jdonville:  thanks for the lead.  i used it and it worked great.  before i had to print, sign and then re-scan so i could upload them to our clients site for the contractor to print out.  the banjo plug in allows the electronic signature to be compliant with the texas board rules.
hmm.. i might have to check it out also.