/**
* generate an enveloped object that contains an CMS Enveloped Data
* object using the given provider and the passed in key generator.
*/
private CmsAuthenticatedData Generate(
CmsProcessable content,
string macOid,
CipherKeyGenerator keyGen)
{
AlgorithmIdentifier macAlgId;
KeyParameter encKey;
Asn1OctetString encContent;
Asn1OctetString macResult;
try
{
// FIXME Will this work for macs?
byte[] encKeyBytes = keyGen.GenerateKey();
encKey = ParameterUtilities.CreateKeyParameter(macOid, encKeyBytes);
Asn1Encodable asn1Params = GenerateAsn1Parameters(macOid, encKeyBytes);
ICipherParameters cipherParameters;
macAlgId = GetAlgorithmIdentifier(
macOid, encKey, asn1Params, out cipherParameters);
IMac mac = MacUtilities.GetMac(macOid);
// TODO Confirm no ParametersWithRandom needed
// FIXME Only passing key at the moment
// mac.Init(cipherParameters);
mac.Init(encKey);
MemoryStream bOut = new MemoryStream();
Stream mOut = new TeeOutputStream(bOut, new MacOutputStream(mac));
content.Write(mOut);
mOut.Dispose();
bOut.Dispose();
encContent = new BerOctetString(bOut.ToArray());
byte[] macOctets = MacUtilities.DoFinal(mac);
macResult = new DerOctetString(macOctets);
}
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);
}
Asn1EncodableVector recipientInfos = new Asn1EncodableVector();
foreach (RecipientInfoGenerator rig in recipientInfoGenerators)
{
try
{
recipientInfos.Add(rig.Generate(encKey, rand));
}
catch (InvalidKeyException e)
{
throw new CmsException("key inappropriate for algorithm.", e);
}
catch (GeneralSecurityException e)
{
throw new CmsException("error making encrypted content.", e);
}
}
ContentInfo eci = new ContentInfo(CmsObjectIdentifiers.Data, encContent);
ContentInfo contentInfo = new ContentInfo(
CmsObjectIdentifiers.AuthenticatedData,
new AuthenticatedData(null, new DerSet(recipientInfos), macAlgId, null, eci, null, macResult, null));
return new CmsAuthenticatedData(contentInfo);
}
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.ObjectID);
// 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);
}
}