SignedSignatureProperties.cs

// SignedSignatureProperties.cs
//
// XAdES Starter Kit for Microsoft .NET 3.5 (and above)
// 2010 Microsoft France
// Published under the CECILL-B Free Software license agreement.
// (http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.txt)
// 
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 
// WHETHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 
// WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. 
// THE ENTIRE RISK OF USE OR RESULTS IN CONNECTION WITH THE USE OF THIS CODE 
// AND INFORMATION REMAINS WITH THE USER. 
//

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

namespace Microsoft.Xades
{
	/// <summary>
	/// The properties that qualify the signature itself or the signer are
	/// included as content of the SignedSignatureProperties element
	/// </summary>
	public class SignedSignatureProperties
	{
		#region Private variables
		private DateTime signingTime;
		private SigningCertificate signingCertificate;
		private SignaturePolicyIdentifier signaturePolicyIdentifier;
		private SignatureProductionPlace signatureProductionPlace;
		private SignerRole signerRole;
		#endregion

		#region Public properties
		/// <summary>
		/// The signing time property specifies the time at which the signer
		/// performed the signing process. This is a signed property that
		/// qualifies the whole signature. An XML electronic signature aligned
		/// with the present document MUST contain exactly one SigningTime element .
		/// </summary>
		public DateTime SigningTime
		{
			get
			{
				return this.signingTime;
			}
			set
			{
				this.signingTime = value;
			}
		}

		/// <summary>
		/// The SigningCertificate property is designed to prevent the simple
		/// substitution of the certificate. This property contains references
		/// to certificates and digest values computed on them. The certificate
		/// used to verify the signature shall be identified in the sequence;
		/// the signature policy may mandate other certificates be present,
		/// that may include all the certificates up to the point of trust.
		/// This is a signed property that qualifies the signature. An XML
		/// electronic signature aligned with the present document MUST contain
		/// exactly one SigningCertificate.
		/// </summary>
		public SigningCertificate SigningCertificate
		{
			get
			{
				return this.signingCertificate;
			}
			set
			{
				this.signingCertificate = value;
			}
		}

		/// <summary>
		/// The signature policy is a set of rules for the creation and
		/// validation of an electronic signature, under which the signature
		/// can be determined to be valid. A given legal/contractual context
		/// may recognize a particular signature policy as meeting its
		/// requirements.
		/// An XML electronic signature aligned with the present document MUST
		/// contain exactly one SignaturePolicyIdentifier element.
		/// </summary>
		public SignaturePolicyIdentifier SignaturePolicyIdentifier
		{
			get
			{
				return this.signaturePolicyIdentifier;
			}
			set
			{
				this.signaturePolicyIdentifier = value;
			}
		}

		/// <summary>
		/// In some transactions the purported place where the signer was at the time
		/// of signature creation may need to be indicated. In order to provide this
		/// information a new property may be included in the signature.
		/// This property specifies an address associated with the signer at a
		/// particular geographical (e.g. city) location.
		/// This is a signed property that qualifies the signer.
		/// An XML electronic signature aligned with the present document MAY contain
		/// at most one SignatureProductionPlace element.
		/// </summary>
		public SignatureProductionPlace SignatureProductionPlace
		{
			get
			{
				return this.signatureProductionPlace;
			}
			set
			{
				this.signatureProductionPlace = value;
			}
		}

		/// <summary>
		/// According to what has been stated in the Introduction clause, an
		/// electronic signature produced in accordance with the present document
		/// incorporates: "a commitment that has been explicitly endorsed under a
		/// signature policy, at a given time, by a signer under an identifier,
		/// e.g. a name or a pseudonym, and optionally a role".
		/// While the name of the signer is important, the position of the signer
		/// within a company or an organization can be even more important. Some
		/// contracts may only be valid if signed by a user in a particular role,
		/// e.g. a Sales Director. In many cases who the sales Director really is,
		/// is not that important but being sure that the signer is empowered by his
		/// company to be the Sales Director is fundamental.
		/// </summary>
		public SignerRole SignerRole
		{
			get
			{
				return this.signerRole;
			}
			set
			{
				this.signerRole = value;
			}
		}
		#endregion

		#region Constructors
		/// <summary>
		/// Default constructor
		/// </summary>
		public SignedSignatureProperties()
		{
			this.signingTime = DateTime.MinValue;
			this.signingCertificate = new SigningCertificate();
			this.signaturePolicyIdentifier = new SignaturePolicyIdentifier();
			this.signatureProductionPlace = new SignatureProductionPlace();
			this.signerRole = new SignerRole();
		}
		#endregion

		#region Public methods
		/// <summary>
		/// Check to see if something has changed in this instance and needs to be serialized
		/// </summary>
		/// <returns>Flag indicating if a member needs serialization</returns>
		public bool HasChanged()
		{ //Should always be serialized
			bool retVal = false;

			retVal = true;

			return retVal;
		}

		/// <summary>
		/// Load state from an XML element
		/// </summary>
		/// <param name="xmlElement">XML element containing new state</param>
		public void LoadXml(System.Xml.XmlElement xmlElement)
		{
			XmlNamespaceManager xmlNamespaceManager;
			XmlNodeList xmlNodeList;
			
			if (xmlElement == null)
			{
				throw new ArgumentNullException("xmlElement");
			}

			xmlNamespaceManager = new XmlNamespaceManager(xmlElement.OwnerDocument.NameTable);
			xmlNamespaceManager.AddNamespace("xsd", XadesSignedXml.XadesNamespaceUri);

			xmlNodeList = xmlElement.SelectNodes("xsd:SigningTime", xmlNamespaceManager);
			if (xmlNodeList.Count == 0)
			{
				throw new CryptographicException("SigningTime missing");
			}
            this.signingTime = XmlConvert.ToDateTime(xmlNodeList.Item(0).InnerText, XmlDateTimeSerializationMode.Local);

			xmlNodeList = xmlElement.SelectNodes("xsd:SigningCertificate", xmlNamespaceManager);
			if (xmlNodeList.Count == 0)
			{
				throw new CryptographicException("SigningCertificate missing");
			}
			this.signingCertificate = new SigningCertificate();
			this.signingCertificate.LoadXml((XmlElement)xmlNodeList.Item(0));

			xmlNodeList = xmlElement.SelectNodes("xsd:SignaturePolicyIdentifier", xmlNamespaceManager);
			if (xmlNodeList.Count == 0)
			{
				throw new CryptographicException("SignaturePolicyIdentifier missing");
			}
			this.signaturePolicyIdentifier = new SignaturePolicyIdentifier();
			this.signaturePolicyIdentifier.LoadXml((XmlElement)xmlNodeList.Item(0));

			xmlNodeList = xmlElement.SelectNodes("xsd:SignatureProductionPlace", xmlNamespaceManager);
			if (xmlNodeList.Count != 0)
			{
				this.signatureProductionPlace = new SignatureProductionPlace();
				this.signatureProductionPlace.LoadXml((XmlElement)xmlNodeList.Item(0));
			}
			else
			{
				this.signatureProductionPlace = null;
			}

			xmlNodeList = xmlElement.SelectNodes("xsd:SignerRole", xmlNamespaceManager);
			if (xmlNodeList.Count != 0)
			{
				this.signerRole = new SignerRole();
				this.signerRole.LoadXml((XmlElement)xmlNodeList.Item(0));
			}
			else
			{
				this.signerRole = null;
			}
		}

		/// <summary>
		/// Returns the XML representation of the this object
		/// </summary>
		/// <returns>XML element containing the state of this object</returns>
		public XmlElement GetXml()
		{
			XmlDocument creationXmlDocument;
			XmlElement retVal;
			XmlElement bufferXmlElement;

			creationXmlDocument = new XmlDocument();
			retVal = creationXmlDocument.CreateElement("SignedSignatureProperties", XadesSignedXml.XadesNamespaceUri);

			if (this.signingTime == DateTime.MinValue)
			{ //SigningTime should be available
				this.signingTime = DateTime.Now;
			}
			bufferXmlElement = creationXmlDocument.CreateElement("SigningTime", XadesSignedXml.XadesNamespaceUri);
			bufferXmlElement.InnerText = Convert.ToString(this.signingTime.ToString("s")); //ISO 8601 format as required in http://www.w3.org/TR/xmlschema-2/#dateTime 
			retVal.AppendChild(bufferXmlElement);

			if (this.signingCertificate != null && this.signingCertificate.HasChanged())
			{
				retVal.AppendChild(creationXmlDocument.ImportNode(this.signingCertificate.GetXml(), true));
			}
			else
			{
				throw new CryptographicException("SigningCertificate element missing in SignedSignatureProperties");
			}

			if (this.signaturePolicyIdentifier != null && this.signaturePolicyIdentifier.HasChanged())
			{
				retVal.AppendChild(creationXmlDocument.ImportNode(this.signaturePolicyIdentifier.GetXml(), true));
			}
			else
			{
				throw new CryptographicException("SignaturePolicyIdentifier element missing in SignedSignatureProperties");
			}

			if (this.signatureProductionPlace != null && this.signatureProductionPlace.HasChanged())
			{
				retVal.AppendChild(creationXmlDocument.ImportNode(this.signatureProductionPlace.GetXml(), true));
			}

			if (this.signerRole != null && this.signerRole.HasChanged())
			{
				retVal.AppendChild(creationXmlDocument.ImportNode(this.signerRole.GetXml(), true));
			}

			return retVal;
		}
		#endregion
	}
}