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program when decrypting XML - Unable to retrieve the decryption key

P: n/a
When decrypt the xml, output "Unable to retrieve the decryption key."
Can anyone help me solve the problem?

I got the code from http://msdn.microsoft.com/en-us/library/ms229746.aspx
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 CspParameters object to specify
// a key container.
CspParameters cspParams = new CspParameters();
cspParams.KeyContainerName = "XML_ENC_RSA_KEY";

// Create a new RSA key and save it in the container. This key will
encrypt
// a symmetric key, which will then be encryped in the XML document.
RSACryptoServiceProvider rsaKey = new
RSACryptoServiceProvider(cspParams);

try
{
// Encrypt the "creditcard" element.
Encrypt(xmlDoc, "creditcard", "EncryptedElement1", rsaKey,
"rsaKey");
// Save the XML document.
xmlDoc.Save("test_Encrypted.xml");

// Display the encrypted XML to the console.
Console.WriteLine("Encrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlDoc.OuterXml);

}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
// Clear the RSA key.
rsaKey.Clear();
}
// Create an XmlDocument object.
xmlDoc = new XmlDocument();

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

// Get the RSA key from the key container. This key will decrypt
// a symmetric key that was imbedded in the XML document.
rsaKey = new RSACryptoServiceProvider(cspParams);

try
{

// Decrypt the elements.
Decrypt(xmlDoc, rsaKey, "rsaKey");
// Display the encrypted XML to the console.
Console.WriteLine();
Console.WriteLine("Decrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlDoc.OuterXml);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
// Clear the RSA key.
rsaKey.Clear();
}

Console.ReadLine();
}

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

////////////////////////////////////////////////
// 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");

}
RijndaelManaged sessionKey = null;

try
{
//////////////////////////////////////////////////
// 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.
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;
edElement.Id = EncryptionElementID;
// 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);

// Create a new DataReference element
// for the KeyInfo element. This optional
// element specifies which EncryptedData
// uses this key. An XML document can have
// multiple EncryptedData elements that use
// different keys.
DataReference dRef = new DataReference();

// Specify the EncryptedData URI.
dRef.Uri = "#" + EncryptionElementID;

// Add the DataReference to the EncryptedKey.
ek.AddReference(dRef);
// Add the encrypted key to the
// EncryptedData object.

edElement.KeyInfo.AddClause(new KeyInfoEncryptedKey(ek));
// 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 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);
}
catch (Exception e)
{
// re-throw the exception.
throw e;
}
finally
{
if (sessionKey != null)
{
sessionKey.Clear();
}

}

}
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();

}

}
Jun 27 '08 #1
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P: n/a
Any idea?
"Elliot" <el************@hotmail.co.ukwrote in message
news:EF**********************************@microsof t.com...
When decrypt the xml, output "Unable to retrieve the decryption key."
Can anyone help me solve the problem?

I got the code from http://msdn.microsoft.com/en-us/library/ms229746.aspx
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 CspParameters object to specify
// a key container.
CspParameters cspParams = new CspParameters();
cspParams.KeyContainerName = "XML_ENC_RSA_KEY";

// Create a new RSA key and save it in the container. This key
will encrypt
// a symmetric key, which will then be encryped in the XML
document.
RSACryptoServiceProvider rsaKey = new
RSACryptoServiceProvider(cspParams);

try
{
// Encrypt the "creditcard" element.
Encrypt(xmlDoc, "creditcard", "EncryptedElement1", rsaKey,
"rsaKey");
// Save the XML document.
xmlDoc.Save("test_Encrypted.xml");

// Display the encrypted XML to the console.
Console.WriteLine("Encrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlDoc.OuterXml);

}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
// Clear the RSA key.
rsaKey.Clear();
}
// Create an XmlDocument object.
xmlDoc = new XmlDocument();

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

// Get the RSA key from the key container. This key will decrypt
// a symmetric key that was imbedded in the XML document.
rsaKey = new RSACryptoServiceProvider(cspParams);

try
{

// Decrypt the elements.
Decrypt(xmlDoc, rsaKey, "rsaKey");
// Display the encrypted XML to the console.
Console.WriteLine();
Console.WriteLine("Decrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlDoc.OuterXml);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
// Clear the RSA key.
rsaKey.Clear();
}

Console.ReadLine();
}

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

////////////////////////////////////////////////
// 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");

}
RijndaelManaged sessionKey = null;

try
{
//////////////////////////////////////////////////
// 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.
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;
edElement.Id = EncryptionElementID;
// 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);

// Create a new DataReference element
// for the KeyInfo element. This optional
// element specifies which EncryptedData
// uses this key. An XML document can have
// multiple EncryptedData elements that use
// different keys.
DataReference dRef = new DataReference();

// Specify the EncryptedData URI.
dRef.Uri = "#" + EncryptionElementID;

// Add the DataReference to the EncryptedKey.
ek.AddReference(dRef);
// Add the encrypted key to the
// EncryptedData object.

edElement.KeyInfo.AddClause(new KeyInfoEncryptedKey(ek));
// 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 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);
}
catch (Exception e)
{
// re-throw the exception.
throw e;
}
finally
{
if (sessionKey != null)
{
sessionKey.Clear();
}

}

}
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();

}

}

Jun 27 '08 #2

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