void signContent(MessageSigner messageSigner, Byte[] content)
{
hashAlgId = new AlgorithmIdentifier(messageSigner.HashingAlgorithm.ToOid(), new Byte[0]);
pubKeyAlgId = new AlgorithmIdentifier(messageSigner.PublicKeyAlgorithm, new Byte[0]);
prepareSigning(content);
SignedContentBlob signedBlob;
if (_authAttributes.Any())
{
// auth attributes are encoded as IMPLICIT (OPTIONAL), but RFC2315 §9.3 requires signature computation for SET
var attrBytes = _authAttributes.Encode();
attrBytes[0] = 0x31;
signedBlob = new SignedContentBlob(attrBytes, ContentBlobType.ToBeSignedBlob);
}
else
{
if (content == null)
{
throw new ArgumentException("'content' parameter cannot be null if no authenticated attributes present.");
}
signedBlob = new SignedContentBlob(content, ContentBlobType.ToBeSignedBlob);
}
signerCert = new PkcsSubjectIdentifier(messageSigner.SignerCertificate, SubjectIdentifier);
signedBlob.Sign(messageSigner);
hashValue = signedBlob.Signature.Value;
}
/// <summary>
/// Encodes and signs the content using the signer object used in
/// </summary>
/// <returns>
/// An instance of <see cref="PkcsSignerInfo"/> class.
/// </returns>
/// <remarks>
/// Before signing, the method adds two authenticated attributes: content type and message digest. Authenticated attributes are then
/// signed with signer's private key.
/// </remarks>
public PkcsSignerInfo Encode()
{
if (_authAttributes.All(x => x.Oid.Value != MESSAGE_DIGEST))
{
throw new InvalidOperationException();
}
// version
var builder = new Asn1Builder().AddInteger(Version);
// signerIdentifier
builder.AddDerData(signerCert.Encode());
// digestAlgorithm
builder.AddDerData(hashAlgId.RawData);
// authenticatedAttributes
if (_authAttributes.Any())
{
builder.AddExplicit(0, _authAttributes.Encode(), false);
}
// digestEncryptionAlgorithm
builder.AddDerData(pubKeyAlgId.RawData);
// encryptedDigest
builder.AddOctetString(hashValue);
// unauthenticatedAttributes
if (_unauthAttributes.Any())
{
builder.AddExplicit(1, UnauthenticatedAttributes.Encode(), false);
}
// wrap
return(new PkcsSignerInfo(builder.GetEncoded()));
}