protected Stream Open(
Stream outStr,
AlgorithmIdentifier macAlgId,
ICipherParameters cipherParameters,
Asn1EncodableVector recipientInfos)
{
try
{
//
// ContentInfo
//
BerSequenceGenerator cGen = new BerSequenceGenerator(outStr);
cGen.AddObject(CmsObjectIdentifiers.AuthenticatedData);
//
// Authenticated Data
//
BerSequenceGenerator authGen = new BerSequenceGenerator(
cGen.GetRawOutputStream(), 0, true);
authGen.AddObject(new DerInteger(AuthenticatedData.CalculateVersion(null)));
Stream authRaw = authGen.GetRawOutputStream();
Asn1Generator recipGen = _berEncodeRecipientSet
? (Asn1Generator) new BerSetGenerator(authRaw)
: new DerSetGenerator(authRaw);
foreach (Asn1Encodable ae in recipientInfos)
{
recipGen.AddObject(ae);
}
recipGen.Close();
authGen.AddObject(macAlgId);
BerSequenceGenerator eiGen = new BerSequenceGenerator(authRaw);
eiGen.AddObject(CmsObjectIdentifiers.Data);
Stream octetOutputStream = CmsUtilities.CreateBerOctetOutputStream(
eiGen.GetRawOutputStream(), 0, false, _bufferSize);
IMac mac = MacUtilities.GetMac(macAlgId.Algorithm);
// TODO Confirm no ParametersWithRandom needed
mac.Init(cipherParameters);
Stream mOut = new TeeOutputStream(octetOutputStream, new MacOutputStream(mac));
return(new CmsAuthenticatedDataOutputStream(mOut, mac, cGen, authGen, eiGen));
}
catch (SecurityUtilityException e)
{
throw new CmsException("couldn't create cipher.", e);
}
catch (InvalidKeyException e)
{
throw new CmsException("key invalid in message.", e);
}
catch (IOException e)
{
throw new CmsException("exception decoding algorithm parameters.", e);
}
}
