Support for 256-bit AES (proprietary extension in Acrobat 9)

Q: We would like to use PDFTron PDFNet for .NET to encrypt and process
PDF documents. Among other features we would like to encrypt
PDF documents with AES 256 bits which is supported by Acrobat 9.

Would you kindly tell me if PDFNet can support this requirement? Or if
not, when will
it be supported?
A: At the moment, PDFNet supports AES encryption which is part of
ISO32000 standard. Starting with Acrobat 9, Adobe introduced a
_proprietary_ AES 256-bit encryption. The security handler is already
implemented and is available as part of an unoffical PDFNet build.
Also, the hanlder will be offically supported as part of the next
PDFNet update.

Please keep in mind that in practice this encryption algorithm is
weaker than standard AES encryption (for more info, please see,,

As a result, PDFTron does not recommend use of Adobe's AES-256
security handler due to compatibility, standards compliance, and
security issues.