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EncryptedType.MimeType Property

Gets or sets the MimeType attribute of an EncryptedType instance in XML encryption.

Namespace:  System.Security.Cryptography.Xml
Assembly:  System.Security (in System.Security.dll)

public virtual string MimeType { get; set; }

Property Value

Type: System.String
A string that describes the media type of the encrypted data.

The MimeType attribute is an optional attribute that describes the media type of the encrypted data. The value of this attribute is a string with values defined by RFC 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies. For example, if the data that is encrypted is a base64-encoded PNG, the Encoding attribute would be 'http://www.w3.org/2000/09/xmldsig#base64' and the MimeType would be 'image/png'. This attribute is optional and no validation of the MimeType information is required. The attribute does not indicate that the encryption application must do any additional processing. Note that this information may not be necessary if it is already bound to the identifier in the Type attribute.

The following example demonstrates how to encrypt and decrypt an XML element by using the EncryptedData class that derives from the EncryptedType class. This example then displays various properties of the EncryptedData class to the console.

using System;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;

class Program
{
	static void Main(string[] args)
	{

		// Create an XmlDocument object.
		XmlDocument xmlDoc = new XmlDocument();

		// Load an XML file into the XmlDocument object. 
		try
		{
			xmlDoc.PreserveWhitespace = true;
			xmlDoc.Load("test.xml");
		}
		catch (Exception e)
		{
			Console.WriteLine(e.Message);
		}

		// Create a new RSA key.  This key will encrypt a symmetric key, 
		// which will then be imbedded in the XML document.  
		RSA rsaKey = new RSACryptoServiceProvider();


		try
		{
			// Encrypt the "creditcard" element.
			Encrypt(xmlDoc, "creditcard", rsaKey, "rsaKey");

			// Inspect the EncryptedKey element.
			InspectElement(xmlDoc);

			// Decrypt the "creditcard" element.
			Decrypt(xmlDoc, rsaKey, "rsaKey");

		}
		catch (Exception e)
		{
			Console.WriteLine(e.Message);
		}
		finally
		{
			// Clear the RSA key.
			rsaKey.Clear();
		}

	}

	public static void Encrypt(XmlDocument Doc, string ElementToEncrypt, RSA Alg, string KeyName)
	{
		// Check the arguments.   
		if (Doc == null)
			throw new ArgumentNullException("Doc");
		if (ElementToEncrypt == null)
			throw new ArgumentNullException("ElementToEncrypt");
		if (Alg == null)
			throw new ArgumentNullException("Alg");

		//////////////////////////////////////////////// 
		// Find the specified element in the XmlDocument 
		// object and create a new XmlElemnt object. 
		////////////////////////////////////////////////

		XmlElement elementToEncrypt = Doc.GetElementsByTagName(ElementToEncrypt)[0] as XmlElement;

		// Throw an XmlException if the element was not found. 
		if (elementToEncrypt == null)
		{
			throw new XmlException("The specified element was not found");

		}

		////////////////////////////////////////////////// 
		// Create a new instance of the EncryptedXml class  
		// and use it to encrypt the XmlElement with the  
		// a new random symmetric key. 
		////////////////////////////////////////////////// 

		// Create a 256 bit Rijndael key.
		RijndaelManaged sessionKey = new RijndaelManaged();
		sessionKey.KeySize = 256;

		EncryptedXml eXml = new EncryptedXml();

		byte[] encryptedElement = eXml.EncryptData(elementToEncrypt, sessionKey, false);

		//////////////////////////////////////////////// 
		// Construct an EncryptedData object and populate 
		// it with the desired encryption information. 
		////////////////////////////////////////////////


		EncryptedData edElement = new EncryptedData();
		edElement.Type = EncryptedXml.XmlEncElementUrl;

		// Create an EncryptionMethod element so that the  
		// receiver knows which algorithm to use for decryption.

		edElement.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncAES256Url);

		// Encrypt the session key and add it to an EncryptedKey element.
		EncryptedKey ek = new EncryptedKey();

		byte[] encryptedKey = EncryptedXml.EncryptKey(sessionKey.Key, Alg, false);

		ek.CipherData = new CipherData(encryptedKey);

		ek.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncRSA15Url);

		// Set the KeyInfo element to specify the 
		// name of the RSA key. 

		// Create a new KeyInfo element.
		edElement.KeyInfo = new KeyInfo();

		// Create a new KeyInfoName element.
		KeyInfoName kin = new KeyInfoName();

		// Specify a name for the key.
		kin.Value = KeyName;

		// Add the KeyInfoName element to the  
		// EncryptedKey object.
		ek.KeyInfo.AddClause(kin);

		// Add the encrypted key to the  
		// EncryptedData object.

		edElement.KeyInfo.AddClause(new KeyInfoEncryptedKey(ek));

		// Add the encrypted element data to the  
		// EncryptedData object.
		edElement.CipherData.CipherValue = encryptedElement;

		//////////////////////////////////////////////////// 
		// Replace the element from the original XmlDocument 
		// object with the EncryptedData element. 
		////////////////////////////////////////////////////

		EncryptedXml.ReplaceElement(elementToEncrypt, edElement, false);

	}

	public static void Decrypt(XmlDocument Doc, RSA Alg, string KeyName)
	{
		// Check the arguments.   
		if (Doc == null)
			throw new ArgumentNullException("Doc");
		if (Alg == null)
			throw new ArgumentNullException("Alg");
		if (KeyName == null)
			throw new ArgumentNullException("KeyName");

		// Create a new EncryptedXml object.
		EncryptedXml exml = new EncryptedXml(Doc);

		// Add a key-name mapping. 
		// This method can only decrypt documents 
		// that present the specified key name.
		exml.AddKeyNameMapping(KeyName, Alg);

		// Decrypt the element.
		exml.DecryptDocument();

	}

	static void InspectElement(XmlDocument Doc)
	{
		// Get the EncryptedData element from the XMLDocument object.
		XmlElement encryptedData = Doc.GetElementsByTagName("EncryptedData")[0] as XmlElement;

		// Create a new EncryptedData object.
		EncryptedData encData = new EncryptedData();

		// Load the XML from the document to 
		// initialize the EncryptedData object.
		encData.LoadXml(encryptedData);

		// Display the properties. 
		// Most values are Null by default.


		
		Console.WriteLine("EncryptedData.CipherData: " + encData.CipherData.GetXml().InnerXml);
		Console.WriteLine("EncryptedData.Encoding: " + encData.Encoding);
		Console.WriteLine("EncryptedData.EncryptionMethod: " + encData.EncryptionMethod.GetXml().InnerXml);
		if (encData.EncryptionProperties.Count >= 1)
		{
			Console.WriteLine("EncryptedData.EncryptionProperties: " + encData.EncryptionProperties[0].GetXml().InnerXml);
		}

		Console.WriteLine("EncryptedData.Id: " + encData.Id);
		Console.WriteLine("EncryptedData.KeyInfo: " + encData.KeyInfo.GetXml().InnerXml);
		Console.WriteLine("EncryptedData.MimeType: " + encData.MimeType);
	}

}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

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