How to create table and digital signature ?

Question

Hello,
I would like to ask two questions regarding SAP interactive forms by adobe.
1st question:
How to create table in interactive form?
Table that i can add rows and column and will show it in the form.
Example the rows and columns that i want:
<u><b>ID:</b></u>                <b><u>Name:  </u>  </b>               <u><b>DOB:</b></u>
1                  Jack                      01/02/80
2                  Ivy                         10/12/82
2nd question:
How to create digital signature ?
I'm creating a adobe forms which need employee to sign on the form. I use signature field at my form. However, i don't know how to create a new signature and insert in the signature field.
Can any one provide the answer with step by step guide?
Thanks a lot

Answer 1

Hi Pradeepa,
you said you have your digital signature in
BMP format? That means Bitmap and would mean you are actually talking about a picture! THIS IS NOT A DIGITAL SIGNATURE!
A digital signature is a cryptographic key (aka public key cryptography) that is used to digitally sign a document, or at least a hash value derived from the document. Digitally signing means, applying the key in a well defined way (this is the algorithm used) to the document or hash value. You do this with your private key and the receiver of the document can then use your public key (which you can distribute in any way you want, even unsecure) to unencrypt the hash value. If this succeeds the receiver knows that the document was signed by you.
This is because both keys are mathematically related in such a way, that what one key encrypted can only be decrypted by the corresponding other key and by no other key. You even can´t decrypt a document with the same key it was encrypted with, this is the difference to symmetric encryption - please have a look at help.sap.com and search for digital signatures.
The named formats (afs, pfx and p12) are ways of coding the key, together with information about your person, such as email address and information about validity of the key into a
certificate. This type of certificate is then called a x.509 certificate and is the same you might have seen when connecting to a secure webserver such as the one of your bank website. 
Signing a form with such a certificate provides for mathematically and therefore business related proove of a users identity.
In case you are really using a bitmap, this cannot work and would not serve you any good.
Ask yourself this question: I want to make sure that the form was signed by a specific person. How can I make sure that the signing can only be done by the person pretending to have done so?
A bitmap contains a picture, probably of the persons handwritten signature. How can I make sure that this picture was NOT recreated in MS Paint or Photoshop by someone else?
The answer is:
you can't! Therefore this way of prooving identity is useless. 
You need to provide your users with digital signatures, put these in the certificate cache of your IE.  If a user then clicks on the signing field, the private key is used to digitally sign the form - create a hash value of the form and encrypt it with the private key. After the form is send back to the server or you, you use the corresponding public key to decrypt the hash value and, as said above, if this succeeds, identity of the signer is proven.
THIS IS AN OVERSIMPLIFICATION! You might want to take a look at Adobe Reader Credentials.
Regards,
   Christian