Munich-based software developer PDFlib GmbH has released PDFlib PLOP 3. In a related development, the company also launched the new product PLOP DS, used for digitally signing PDF documents.
New and improved features in PLOP 3 include AES encryption, integrated pCOS interface for analyzing PDF, and a repair and optimization mode for input PDF documents. In addition, document and XMP metadata can be retrieved and set. The new product, PLOP DS, includes all of the features of PLOP 3, but adds the ability to apply digital signatures to documents. The signatures can then be validated in Adobe Acrobat and Adobe Reader.
PDFlib PLOP supports 128-bit encryption with the AES algorithm (Advanced Encryption Standard) as supported by Acrobat 7. AES encryption is considered much more secure than earlier crypto algorithms.
OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.