/// <summary>
/// See IDigitalSignatureProvider
/// </summary>
Guid IDigitalSignatureProvider.AddRequestSignature(DigitalSignature digitalSignature)
{
AssertIsSignable();
// Create guid used for signature ID
Guid guidID = Guid.NewGuid();
// Create a new SignatureDefinition
XpsSignatureDefinition xpsSignatureDefinition = new XpsSignatureDefinition();
// Use the digSig to setup the SignatureDefinition.
xpsSignatureDefinition.RequestedSigner = digitalSignature.SubjectName;
xpsSignatureDefinition.Intent = digitalSignature.Reason;
xpsSignatureDefinition.SigningLocale = digitalSignature.Location;
xpsSignatureDefinition.SignBy = digitalSignature.SignedOn;
// Use our new guid to setup the ID
xpsSignatureDefinition.SpotId = guidID;
// Add the signature definition to the document
FixedDocument.AddSignatureDefinition(xpsSignatureDefinition);
FixedDocument.CommitSignatureDefinition();
// Set the signature's status to Not Signed before adding to our list
digitalSignature.SignatureState = SignatureStatus.NotSigned;
// Add the new signature to our list of signatures and definitions
DigitalSignatureList.Add(digitalSignature);
return(guidID);
}
/// <summary>
/// See IDigitalSignatureProvider
/// </summary>
void IDigitalSignatureProvider.RemoveRequestSignature(Guid spotId)
{
AssertIsSignable();
XpsSignatureDefinition definition = FindSignatureDefinition(spotId);
if (definition != null)
{
FixedDocument.RemoveSignatureDefinition(definition);
FixedDocument.CommitSignatureDefinition();
}
// Loop through the signature list and remove the entry for the
// requested signature
foreach (DigitalSignature signature in DigitalSignatureList)
{
if (signature.GuidID == spotId)
{
// We only want to remove unsigned signature definitions
// (requested signatures) and not actual signatures.
if (signature.SignatureState == SignatureStatus.NotSigned)
{
DigitalSignatureList.Remove(signature);
}
// It is safe to remove an element from the list that we're
// currently enumerating because we stop enumerating as soon
// as we find the element we're looking for.
break;
}
}
}
/// <summary>
/// See IDigitalSignatureProvider
/// </summary>
void IDigitalSignatureProvider.SignDocument(DigitalSignature digitalSignature)
{
AssertIsSignable();
XpsDigSigPartAlteringRestrictions reachRestrictions = XpsDigSigPartAlteringRestrictions.None;
if (digitalSignature.IsDocumentPropertiesRestricted)
{
reachRestrictions |= XpsDigSigPartAlteringRestrictions.CoreMetadata;
}
// If additional signatures should invalidate this signature, we
// need to sign the signature origin part
if (digitalSignature.IsAddingSignaturesRestricted)
{
reachRestrictions |= XpsDigSigPartAlteringRestrictions.SignatureOrigin;
}
// a null guid means there was no associated spot, so create a guid
if (digitalSignature.GuidID == null)
{
digitalSignature.GuidID = Guid.NewGuid();
}
XpsDigitalSignature xpsDigitalSignature =
XpsDocument.SignDigitally(
digitalSignature.Certificate,
true,
reachRestrictions,
(Guid)digitalSignature.GuidID,
false /* don't re-verify IsSignable, we've already done it */
);
if (xpsDigitalSignature != null)
{
// Fill in relevant fields from the XPS signature
digitalSignature.XpsDigitalSignature = xpsDigitalSignature;
digitalSignature.SignatureState = SignatureStatus.Valid;
digitalSignature.SignedOn = xpsDigitalSignature.SigningTime;
// Save the simple name from the certificate as the subject name
// in the signature
digitalSignature.SubjectName =
digitalSignature.Certificate.GetNameInfo(
X509NameType.SimpleName,
false /* don't include issuer name */);
// Add the new signature to the list (if it isn't already there).
// That is a possibility since the first signature in a document
// is always added as a signature definition and a signature.
if (!DigitalSignatureList.Contains(digitalSignature))
{
DigitalSignatureList.Add(digitalSignature);
}
}
}
/// <summary>
/// See IDigitalSignatureProvider
/// </summary>
void IDigitalSignatureProvider.UnsignDocument(Guid id)
{
AssertIsSignable();
foreach (DigitalSignature signature in DigitalSignatureList)
{
if (signature.GuidID == id)
{
// Remove the associated XpsDigitalSignature from the
// document
if (signature.XpsDigitalSignature != null)
{
XpsDocument.RemoveSignature(signature.XpsDigitalSignature);
signature.XpsDigitalSignature = null;
}
// Check if the document contains a signature definition
// corresponding to this signature
bool matchesDefinition = (FindSignatureDefinition(id) != null);
// If the signature matches a signature definition in the
// document, mark the signature as NotSigned (i.e. an
// unsigned request) but leave it in the list
if (matchesDefinition)
{
signature.SignatureState = SignatureStatus.NotSigned;
}
else
{
// Remove the signature from the list
DigitalSignatureList.Remove(signature);
}
// It is safe to remove an element from the list that we're
// currently enumerating because we stop enumerating as soon
// as we find the element we're looking for.
break;
}
}
}
