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Passing a password into the pdf security handler

I'm currently working on a project where pdf's can be decrypted after a successful api call that returns the password.
I've browsed through SO and pdftron SDK but can't find a definitive solution on how to insert this password into the security handler.
Things I have tried:
None of the GetSecurityHandler() methods seem to handle password insertion:
SecurityHandler handler = m_PdfDocument.GetSecurityHandler();
Takes a password string but throws error:
m_PdfDocument.InitStdSecurityHandler(pwd);
error: Message: Not a standard security handler. The custom filter needs to be registered.
Judging from the message I assumed I needed m_PdfDocument.InitSecurityHandler() instead, but that method doesn't take a string, only int.
Anyone can bump me onto the right track ?

Thank you for sending the file. This file is encrypted using custom encryption. Your DRM. No PDF reader can open the file, but your own custom PDF reader.
To open the PDF with PDFNet, you need to find out how the file was encrypted in the first place, and essentially do the opposite. I assume the other team that did the encryption was also decrypting, for at least testing purposes?
It might as simple as following example 3 in our Encryption sample. In which case you just need to register under the filter name that the other team used. I think I know what that is, but won't post here, and will email you instead.
But for others, if the PDF was encrypted with a filter called "Frodo", then it would be
CreateDelegate frodo_del = new CreateDelegate(FrodoSecurityHandler.Create);
SecurityManagerSingleton.Instance().RegisterSecurityHandler("Frodo", new SecurityDescriptor("Frodo Security", frodo_del));

Well according to this page, GetSecurityHandler() is used after you initialize another handler, so since InitSecurityHandler() takes an int you could do this
string password = "9quali52ty3";
// Convert the string into a byte[].
byte[] asciiBytes = Encoding.ASCII.GetBytes(password);
string compiledBytes = System.Text.Encoding.ASCII.GetString(asciiBytes);
int convertedBytes = int.Parse(compiledBytes);
m_PdfDocument.InitSecurityHandler(convertedBytes);
m_PdfDocument.GetSecurityHandler();
A good rule of thumb for programming: There is always a way to get from one datatype to another.
Credit to: #Brig Lamoreaux, #Zanoni and #Brandon on the following pages.
Brig Zanoni Brandon

File IO in Windows 8

I have been trying to read a file, and calculate the hash of the contents to find duplicates. The problem is that in Windows 8 (or WinRT or windows store application or however it is called, I'm completely confused), System.IO has been replaced with Windows.Storage, which behaves differently, and is very confusing. The official documentation is not useful at all.
First I need to get a StorageFile object, which in my case, I get from browsing a folder from a file picker:
var picker = new Windows.Storage.Pickers.FolderPicker();
picker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.MusicLibrary;
picker.FileTypeFilter.Add("*");
var folder = await picker.PickSingleFolderAsync();
var files = await folder.GetFilesAsync(Windows.Storage.Search.CommonFileQuery.OrderByName);
Now in files I have the list of files I need to index. Next, I need to open that file:
foreach (StorageFile file in files)
{
var filestream = file.OpenAsync(Windows.Storage.FileAccessMode.Read);
Now is the most confusing part: getting the data from the file. The documentation was useless, and I couldn't find any code example. Apparently, Microsoft thought getting pictures from the camera is more important than opening a file.
The file stream has a member ReadAsync which I think reads the data. This method needs a buffer as a parameter and returns another buffer (???). So I create a buffer:
var buffer = new Windows.Storage.Streams.Buffer(1024 * 1024 * 10); // 10 mb should be enough for an mp3
var resultbuffer = await filestream.ReadAsync(buffer, 1024 * 1024 * 10, Windows.Storage.Streams.InputStreamOptions.ReadAhead);
I am wondering... what happens if the file doesn't have enough bytes? I haven't seen any info in the documentation.
Now I need to calculate the hash for this file. To do that, I need to create an algorithm object...
var alg = Windows.Security.Criptography.Core.HashAlgorithmProvider.OpenAlgorithm("md5");
var hashbuff = alg.HashData(resultbuffer);
// Cleanup
filestream.Dispose();
I also considered reading the file in chunks, but how can I calculate the hash like that? I looked everywhere in the documentation and found nothing about this. Could it be the CryptographicHash class type with it's 'append' method?
Now I have another issue. How can I get the data from that weird buffer thing to a byte array? The IBuffer class doesn't have any 'GetData' member, and the documentation, again, is useless.
So all I could do now is wonder about the mysteries of the universe...
// ???
}
So the question is... how can I do this? I am completely confused, and I wonder why did Microsoft choose to make reading a file so... so... so... impossible! Even in Assembly I could figure it out easier than.... this thing.

WinRT or Windows Runtime should not be confused with .NET as it is not .NET. WinRT has access to only a subset of the Win32 API but not to everything like the .NET is. Here is a pretty good article on what are the rules and restrictions in WinRT.
The WinRT in general does not have access to the file system. It works with capabilities and you can allow file access capability but this would restrict your app's access only to certain areas. Here is a good example of how do to file access via WinRT.

File archiving library/API?

I'm making an application where a document is going to depend on resources and I want them to be embeded into one file. Instead of creating a new format, I was wondering if there was a library or API that already exists to create files with other files embeded in them. It doesn't matter what format it is but I'm looking for one with:
OPTION to encrypt or not encrypt
Can tell wether an existing file is already encrypted or not.
Let's me make my own file extension for it, instead of using one that was created for the format.
Works with .NET 3.5
Are there any libs that you guys would recommend?

You could use DotNetZip library, here is the example using AES encryption
using (ZipFile zip = new ZipFile())
{
zip.AddFile("ReadMe.txt"); // no password for this one
zip.Password= "Cool.Hand.Luke!";
zip.Encryption= EncryptionAlgorithm.WinZipAes256;
zip.AddFile("Rawdata-2008-12-18.csv");
zip.Save("Backup-AES-Encrypted.zip");
}
example is from this page, and when saving you can use any extension you wish.

I'm not sure what you mean by "creating your own format".
There are many ways to archive/encrypt files. You can combine these methods. First encrypt whatever you want to write, and then use an API to write them.
Here are a few resources to create archives:
http://weblogs.asp.net/jgalloway/archive/2007/10/25/creating-zip-archives-in-net-without-an-external-library-like-sharpziplib.aspx
For encryption you can use RSA. Replace your_rsa_key with your RSA key.
var provider = new System.Security.Cryptography.RSACryptoServiceProvider();
provider.ImportParameters(your_rsa_key);
var encryptedBytes = provider.Encrypt(
System.Text.Encoding.UTF8.GetBytes("Hello World!"), true);
string decryptedTest = System.Text.Encoding.UTF8.GetString(
provider.Decrypt(encryptedBytes, true));

How to convert a strongname public key (snk) to <RSAKeyValue>?

I have a file testpublic.snk which holds a public key. I have created it with sn -p c:\test.snk c:\testpublic.snk.
Now, how can I convert testpublic.snk to a string like
<RSAKeyValue><Modulus>z140GwiEJvuGOVqMQUxnojILR8rn2SFOViigoloku59H5eqzqca3Hdyl/jc+Acdb5ktzhBOOyGFElE0/Btlvw9cXVVW8zcT0MBOCaq25D1rSVYLGGM6nXzBrl1XsrBEadZbCgkcF5rw8GaYcYakijaltP1/hvxhbMOARM9VCQ50=</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>
Thanks for your help.

Simply re-use the (MIT.X11 licensed) code from Mono.Security StrongName class, available in github, then call ToXmlString on it's RSA property. Something like:
Console.WriteLine (new StrongName (data).RSA.ToXmlString (false));
Where data is a byte[] containing the content of your snk file. Also you can use true if you want the private key in your XML (it will work if it was available fom your snk file).

MD5 or other Encryption in Silverlight C#

I'm looking to encrypt a password field for use in a login system, therefore I would like to match encryption to make sure the user has entered the correct details.
For some reason Security.Cryptography doesn't have the MD5 services in Silverlight so I'm left looking for a different method.
I had used this before:
public string Md5Encrypt(string originalPassword)
{
//Declarations
Byte[] originalBytes;
Byte[] encodedBytes;
MD5 md5;
//Instantiate MD5CryptoServiceProvider, get bytes for original password and compute hash (encoded password)
md5 = new MD5CryptoServiceProvider();
originalBytes = ASCIIEncoding.Default.GetBytes(originalPassword);
encodedBytes = md5.ComputeHash(originalBytes);
//Convert encoded bytes back to a 'readable' string
return BitConverter.ToString(encodedBytes);
}
But doesn't work now.
Can anyone give me a simple example for a working encryption method in Silverlight C#
Thanks

You can simply use Using HashLib in silverlight: http://hashlib.codeplex.com/ (look inside the HashLib.HashFactory.HashCryptoNotBuildIn namespace)
Also BouncyCastle.Crypt 1.7 release has a Silverlight 2.0 and above build where most crypto/hashing functions are available: http://www.bouncycastle.org/csharp/
And finally to your rescue, Mono source code is always here to rescue you: https://github.com/mono/mono/blob/master/mcs/class/corlib/System.Security.Cryptography/SHA512Managed.cs which you can copy any cypto code to your project if it targets .NET 2.0 or above.