I'm sure that others on the forum would have a better answer for you but I'm going to take a stab at this.
Once you create the form in LiveCycle, open it in Adobe Acrobat Pro. Once open, select File/Save as and from the fly out menu select "Reader Extended PDF" and from that flyout menu, select "Enable Additional Features". Then it will ask you to save it again.
Once you do this, the form can be filled in with the regular Adobe Reader, the form can be saved, and the form can be used for Markup tools, such as sticky notes, redaction, digital stamps with the users' name and date, and digital signatures.
When the person selects to sign the document in the "Extended" section of Adobe Reader X, they will create a self signed signature certificate. Each signature generates it's own serial number. Unfortunately, Adobe doesn't restrict the creation of digital signatures so you can make one in your name, your dog's name, etc and yet all the signatures will validate and look absolutely legitimate.
And unfortunately, the same is true of digital stamps. All you have to do is right click the stamp and you can change the sign on id and forge another's stamp.
I hope this helped for what you are trying to do. Good luck.