/
RSAKeyValue.cs
133 lines (112 loc) · 4.94 KB
/
RSAKeyValue.cs
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Xml;
namespace System.Security.Cryptography.Xml
{
public class RSAKeyValue : KeyInfoClause
{
private RSA _key;
//
// public constructors
//
public RSAKeyValue()
{
_key = RSA.Create();
}
public RSAKeyValue(RSA key)
{
_key = key;
}
//
// public properties
//
public RSA Key
{
get { return _key; }
set { _key = value; }
}
//
// public methods
//
/// <summary>
/// Create an XML representation.
/// </summary>
/// <remarks>
/// Based upon https://www.w3.org/TR/xmldsig-core/#sec-RSAKeyValue.
/// </remarks>
/// <returns>
/// An <see cref="XmlElement"/> containing the XML representation.
/// </returns>
public override XmlElement GetXml()
{
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.PreserveWhitespace = true;
return GetXml(xmlDocument);
}
private const string KeyValueElementName = "KeyValue";
private const string RSAKeyValueElementName = "RSAKeyValue";
private const string ModulusElementName = "Modulus";
private const string ExponentElementName = "Exponent";
internal override XmlElement GetXml(XmlDocument xmlDocument)
{
RSAParameters rsaParams = _key.ExportParameters(false);
XmlElement keyValueElement = xmlDocument.CreateElement(KeyValueElementName, SignedXml.XmlDsigNamespaceUrl);
XmlElement rsaKeyValueElement = xmlDocument.CreateElement(RSAKeyValueElementName, SignedXml.XmlDsigNamespaceUrl);
XmlElement modulusElement = xmlDocument.CreateElement(ModulusElementName, SignedXml.XmlDsigNamespaceUrl);
modulusElement.AppendChild(xmlDocument.CreateTextNode(Convert.ToBase64String(rsaParams.Modulus)));
rsaKeyValueElement.AppendChild(modulusElement);
XmlElement exponentElement = xmlDocument.CreateElement(ExponentElementName, SignedXml.XmlDsigNamespaceUrl);
exponentElement.AppendChild(xmlDocument.CreateTextNode(Convert.ToBase64String(rsaParams.Exponent)));
rsaKeyValueElement.AppendChild(exponentElement);
keyValueElement.AppendChild(rsaKeyValueElement);
return keyValueElement;
}
/// <summary>
/// Deserialize from the XML representation.
/// </summary>
/// <remarks>
/// Based upon https://www.w3.org/TR/xmldsig-core/#sec-RSAKeyValue.
/// </remarks>
/// <param name="value">
/// An <see cref="XmlElement"/> containing the XML representation. This cannot be null.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="value"/> cannot be null.
/// </exception>
/// <exception cref="CryptographicException">
/// The XML has the incorrect schema or the RSA parameters are invalid.
/// </exception>
public override void LoadXml(XmlElement value)
{
if (value is null)
{
throw new ArgumentNullException(nameof(value));
}
if (value.LocalName != KeyValueElementName
|| value.NamespaceURI != SignedXml.XmlDsigNamespaceUrl)
{
throw new CryptographicException(SR.Format(SR.WrongRootElement, KeyValueElementName, SignedXml.XmlDsigNamespaceUrl));
}
const string xmlDsigNamespacePrefix = "dsig";
XmlNamespaceManager xmlNamespaceManager = new XmlNamespaceManager(value.OwnerDocument.NameTable);
xmlNamespaceManager.AddNamespace(xmlDsigNamespacePrefix, SignedXml.XmlDsigNamespaceUrl);
XmlNode rsaKeyValueElement = value.SelectSingleNode($"{xmlDsigNamespacePrefix}:{RSAKeyValueElementName}", xmlNamespaceManager);
if (rsaKeyValueElement == null)
{
throw new CryptographicException(SR.Format(SR.MustContainChildElement, KeyValueElementName, RSAKeyValueElementName));
}
try
{
Key.ImportParameters(new RSAParameters
{
Modulus = Convert.FromBase64String(rsaKeyValueElement.SelectSingleNode($"{xmlDsigNamespacePrefix}:{ModulusElementName}", xmlNamespaceManager).InnerText),
Exponent = Convert.FromBase64String(rsaKeyValueElement.SelectSingleNode($"{xmlDsigNamespacePrefix}:{ExponentElementName}", xmlNamespaceManager).InnerText)
});
}
catch (Exception ex)
{
throw new CryptographicException($"An error occurred parsing the {ModulusElementName} and {ExponentElementName} elements", ex);
}
}
}
}