With help of PDFBlackbox your .NET application can
* Sign and verify PDF documents using RSA public keys and X.509 certificates
* Encrypt and decrypt PDF documents using RSA public keys and X.509 certificates
* Encrypt and decrypt PDF documents using symmetric keys (passwords, passphrases)
* Perform operations using keys stored on cryptographic hardware (USB cryptotokens and smartcards)
* Compress the documents, being processed, using ZLib compression algorithm
* Handle huge PDF documents without significant memory requirements

PDFBlackbox.NET is a comprehensive collection of managed .NET components that help you encrypt, sign and compress PDF documents from your .NET Framework applications.

PDFBlackbox components are a clean-room implementation of PDF format specification, which don't use any third-party libraries for core functionality.

This is .NET edition, which can be integrated into Visual Studio 2008, 2005, 2003, Delphi Prism. It requires .NET Framework 1.1, 2.0, 3.0 or 3.5, Mono (1.0 or 2.0) or .NET CF (1.0, 2.0, 3.5).