Thanks Richard Ramey for his donation, it is the first 10 dollar for the PdfCrypt.
BTW, If you do not want to download PdfCrypt, or you do not have windows system, but still want to remove the PDF Password(either user password or owner password) and stricts(print, copy and so on), please feel free to try my free Remove PDF Password Online solution hosted on Google App Engine(GAE/J), it bases on modified iText 2.1.7.

With PDF Timestamp Signer, we can create Timestamp signature on a PDF without the need of Adobe Acrobat.
You can download it from here.
This version has some limited,

• It only support create visible signature, and put the signature on the left bottom corner(100, 100, 300, 200) of the first page.
• It use http://tss.pki.gva.es:8318/tsa as timestamp server
• It only supports PKCS12 certificate file.
• It run as windows 32 console application, so it has no windows, and only run in Dos command

In Ted Padova’s post, he said,

Adobe Designer 8 supports two different types of forms: Static forms and Dynamic forms. If a form is created as a static form you can easily convert the form in Acrobat 8 to a PDF form.

and he give the steps on how to convert Adobe Designer forms to Acrobat PDF Forms.

This let me thought that I have also done this kind job before, but I did not rely on Adobe Acrobat, just rely iTextSharp, I have used it in my demo software FormServer, and it also have a online demo, Fill and Save PDF Form online, in fact they are the clone of commercial software.
Here is some features about FormServer,

• support automatically convert static PDF forms created by Adobe Designer to Acrobat Form.
• support save data to PDF Forms without Adobe Acrobat, only Adobe reader is enough.
• support save data to FDF

And a HK company found my FormServer, and asked for the source code of “Converting static PDF forms created by Adobe Designer to Acrobat Form”, finally I sold they on US$400.

PS.
With the examples of Bruno Lowagie,Using iText to Fill PDF Forms Created by Adobe Designer, iText can both support Dynamic Forms and Static Forms created by Adobe Designer now.