public void ComputeSignature()
{
if (key != null)
{
if (m_signature.SignedInfo.SignatureMethod == null)
{
//defaults do RSA SHA256 Signature
m_signature.SignedInfo.SignatureMethod = XmlDsigConstants.XmlDsigRSASHA256Url;
}
var sd = SignatureMethodParser.Parse(m_signature.SignedInfo.SignatureMethod);
IDigest hash = XmlEncHashes.GetHashByName(sd.HashName);
DigestReferences();
ISigner signer = null;
// in need for a CryptoConfig factory
if (key is DsaKeyParameters)
{
if (sd.CipherName != "DSA")
{
throw new CryptographicException("DSA SignatureAlgorithm is not supported by the signing key.");
}
signer = new DsaDigestSigner(new DsaSigner(), hash);
}
else if (key is RsaKeyParameters)
{
if (sd.CipherName != "RSA")
{
throw new CryptographicException("RSA SignatureAlgorithm is not supported by the signing key.");
}
signer = new RsaDigestSigner(hash);
}
if (signer != null)
{
signer.Init(true, key);
byte[] signed = SignerHelper.ComputeSignature(signer, SignedInfoTransformed());
m_signature.SignatureValue = signed;
}
}
else
{
throw new CryptographicException("signing key is not specified");
}
}
private byte[] GetReferenceHash(Reference r, bool check_hmac)
{
Stream s = null;
XmlDocument doc = null;
if (r.Uri == String.Empty)
{
doc = envdoc;
}
else if (r.Type == XmlSignature.Uri.Manifest)
{
doc = GetManifest(r);
}
else
{
doc = new XmlDocument();
doc.PreserveWhitespace = true;
string objectName = null;
if (r.Uri.StartsWith("#xpointer"))
{
string uri = string.Join("", r.Uri.Substring(9).Split(whitespaceChars));
if (uri.Length < 2 || uri [0] != '(' || uri [uri.Length - 1] != ')')
{
// FIXME: how to handle invalid xpointer?
uri = String.Empty;
}
else
{
uri = uri.Substring(1, uri.Length - 2);
}
if (uri == "/")
{
doc = envdoc;
}
else if (uri.Length > 6 && uri.StartsWith("id(") && uri [uri.Length - 1] == ')')
{
// id('foo'), id("foo")
objectName = uri.Substring(4, uri.Length - 6);
}
}
else if (r.Uri [0] == '#')
{
objectName = r.Uri.Substring(1);
}
else if (xmlResolver != null)
{
// TODO: test but doc says that Resolver = null -> no access
try {
// no way to know if valid without throwing an exception
Uri uri = new Uri(r.Uri);
s = (Stream)xmlResolver.GetEntity(uri, null, typeof(Stream));
}
catch {
// may still be a local file (and maybe not xml)
s = File.OpenRead(r.Uri);
}
}
if (objectName != null)
{
XmlElement found = null;
foreach (DataObject obj in m_signature.ObjectList)
{
if (obj.Id == objectName)
{
found = obj.GetXml(this.namespaceManager);
found.SetAttribute("xmlns", XmlDsigConstants.XmlDsigNamespaceUrl);
doc.AppendChild(doc.ImportNode(found, true));
// FIXME: there should be theoretical justification of copying namespace declaration nodes this way.
foreach (XmlNode n in found.ChildNodes)
{
// Do not copy default namespace as it must be xmldsig namespace for "Object" element.
if (n.NodeType == XmlNodeType.Element)
{
FixupNamespaceNodes(n as XmlElement, doc.DocumentElement, true);
}
}
break;
}
}
if (found == null && envdoc != null)
{
found = GetIdElement(envdoc, objectName);
if (found != null)
{
doc.AppendChild(doc.ImportNode(found, true));
FixupNamespaceNodes(found, doc.DocumentElement, false);
//Copy root document namespaces to signedproperties
//FixupNamespaceNodes(envdoc.DocumentElement, doc.DocumentElement, false);
}
}
if (found == null)
{
throw new CryptographicException(String.Format("Malformed reference object: {0}", objectName));
}
}
}
if (r.TransformChain.Count > 0)
{
foreach (Transform t in r.TransformChain)
{
if (s == null)
{
s = ApplyTransform(t, doc);
}
else
{
t.LoadInput(s);
object o = t.GetOutput();
if (o is Stream)
{
s = (Stream)o;
}
else
{
s = CanonicalizeOutput(o);
}
}
}
}
else if (s == null)
{
// we must not C14N references from outside the document
// e.g. non-xml documents
if (r.Uri [0] != '#')
{
s = new MemoryStream();
doc.Save(s);
}
else
{
// apply default C14N transformation
s = ApplyTransform(new XmlDsigC14NTransform(), doc);
}
}
//Used to debug the output of the canonicalizer. We are having some problems related to
//different canonicalizer outputs between this implementation and Apache's santuario library.
if (DebugOutput)
{
if (Directory.Exists(DebugOutputFolder))
{
FileStream fs = new FileStream(Path.Combine(DebugOutputFolder, GetSafeFilename("ref" + r.Uri + ".xml")), FileMode.Create);
CopyStream(s, fs);
fs.Close();
s.Position = 0;
}
}
return(XmlEncHashes.ComputeHash(r.DigestMethod, s));
}
