
PDFTK Builder
PDFTK Builder is a free graphical interface to for PDFTK, making it much easier to use. It is a easy to use tool to collate (merge), split, encrypt, decrypt, stamp and rotate (only 90°, 180° or 270°) pdf documents.
PortableSigner is a signing (with X.509 certificates) program for PDF files. It's plattform independent and runs (tested) under Windows (2000, XP, ...), Linux and...
It's possible to sign PDF documents digital with X.509 certificates. This signed documents are read only. Therefore it's possible to implement "electronic paper"
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