What are the restrictions for certificates used to sign or certify pdf documents. I used to do this with no problem using my old certificate that had a key 4k in size. I recently upgraded to a 16k key size. When I sign with that key, I keep getting errors that the document certification is invalid and that the document has been altered or corrupted since it was certified. Since the document was certified just about 2 seconds earlier I have no idea how it could have been altered so it must have been corrupted by my 16k key. Is there a restriction on key size for adobe.
I am using adobe acrobat 8 since I do not see the need to purchase a newer version as that does all that I need.