public CmsEnvelopedDataOutputStream(
CmsEnvelopedGenerator outer,
CipherStream outStream,
BerSequenceGenerator cGen,
BerSequenceGenerator envGen,
BerSequenceGenerator eiGen)
{
_outer = outer;
_out = outStream;
_cGen = cGen;
_envGen = envGen;
_eiGen = eiGen;
}
private Stream Open(
Stream outStream,
AlgorithmIdentifier encAlgID,
ICipherParameters cipherParameters,
Asn1EncodableVector recipientInfos)
{
try
{
//
// ContentInfo
//
BerSequenceGenerator cGen = new BerSequenceGenerator(outStream);
cGen.AddObject(CmsObjectIdentifiers.EnvelopedData);
//
// Encrypted Data
//
BerSequenceGenerator envGen = new BerSequenceGenerator(
cGen.GetRawOutputStream(), 0, true);
envGen.AddObject(this.Version);
Stream envRaw = envGen.GetRawOutputStream();
Asn1Generator recipGen = _berEncodeRecipientSet
? (Asn1Generator) new BerSetGenerator(envRaw)
: new DerSetGenerator(envRaw);
foreach (Asn1Encodable ae in recipientInfos)
{
recipGen.AddObject(ae);
}
recipGen.Close();
BerSequenceGenerator eiGen = new BerSequenceGenerator(envRaw);
eiGen.AddObject(CmsObjectIdentifiers.Data);
eiGen.AddObject(encAlgID);
Stream octetOutputStream = CmsUtilities.CreateBerOctetOutputStream(
eiGen.GetRawOutputStream(), 0, false, _bufferSize);
IBufferedCipher cipher = CipherUtilities.GetCipher(encAlgID.ObjectID);
cipher.Init(true, new ParametersWithRandom(cipherParameters, rand));
CipherStream cOut = new CipherStream(octetOutputStream, null, cipher);
return new CmsEnvelopedDataOutputStream(this, cOut, cGen, envGen, 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);
}
}
/// <summary>
/// <p>
/// Close off the encrypted object - this is equivalent to calling Close() on the stream
/// returned by the Open() method.
/// </p>
/// <p>
/// <b>Note</b>: This does not close the underlying output stream, only the stream on top of
/// it created by the Open() method.
/// </p>
/// </summary>
public void Close()
{
if (cOut != null)
{
// TODO Should this all be under the try/catch block?
if (digestOut != null)
{
//
// hand code a mod detection packet
//
BcpgOutputStream bOut = new BcpgOutputStream(
digestOut, PacketTag.ModificationDetectionCode, 20);
bOut.Flush();
digestOut.Flush();
// TODO
byte[] dig = DigestUtilities.DoFinal(digestOut.WriteDigest());
cOut.Write(dig, 0, dig.Length);
}
cOut.Flush();
try
{
pOut.Write(c.DoFinal());
pOut.Finish();
}
catch (Exception e)
{
throw new IOException(e.Message, e);
}
cOut = null;
pOut = null;
}
}
/// <summary>
/// Generate an enveloped object that contains a CMS Enveloped Data
/// object using the passed in key generator.
/// </summary>
private CmsEnvelopedData Generate(
CmsProcessable content,
string encryptionOid,
CipherKeyGenerator keyGen)
{
AlgorithmIdentifier encAlgId = null;
KeyParameter encKey;
Asn1OctetString encContent;
try
{
byte[] encKeyBytes = keyGen.GenerateKey();
encKey = ParameterUtilities.CreateKeyParameter(encryptionOid, encKeyBytes);
Asn1Encodable asn1Params = GenerateAsn1Parameters(encryptionOid, encKeyBytes);
ICipherParameters cipherParameters;
encAlgId = GetAlgorithmIdentifier(
encryptionOid, encKey, asn1Params, out cipherParameters);
IBufferedCipher cipher = CipherUtilities.GetCipher(encryptionOid);
cipher.Init(true, new ParametersWithRandom(cipherParameters, rand));
MemoryStream bOut = new MemoryStream();
CipherStream cOut = new CipherStream(bOut, null, cipher);
content.Write(cOut);
cOut.Dispose();
encContent = new BerOctetString(bOut.ToArray());
}
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);
}
}
EncryptedContentInfo eci = new EncryptedContentInfo(
CmsObjectIdentifiers.Data,
encAlgId,
encContent);
Asn1Set unprotectedAttrSet = null;
if (unprotectedAttributeGenerator != null)
{
Asn1.Cms.AttributeTable attrTable = unprotectedAttributeGenerator.GetAttributes(Platform.CreateHashtable());
unprotectedAttrSet = new BerSet(attrTable.ToAsn1EncodableVector());
}
ContentInfo contentInfo = new ContentInfo(
CmsObjectIdentifiers.EnvelopedData,
new EnvelopedData(null, new DerSet(recipientInfos), eci, unprotectedAttrSet));
return new CmsEnvelopedData(contentInfo);
}
/// <summary>
/// <p>
/// If buffer is non null stream assumed to be partial, otherwise the length will be used
/// to output a fixed length packet.
/// </p>
/// <p>
/// The stream created can be closed off by either calling Close()
/// on the stream or Close() on the generator. Closing the returned
/// stream does not close off the Stream parameter <c>outStr</c>.
/// </p>
/// </summary>
private Stream Open(
Stream outStr,
long length,
byte[] buffer)
{
if (cOut != null)
throw new InvalidOperationException("generator already in open state");
if (methods.Count == 0)
throw new InvalidOperationException("No encryption methods specified");
if (outStr == null)
throw new ArgumentNullException("outStr");
pOut = new BcpgOutputStream(outStr);
KeyParameter key;
if (methods.Count == 1)
{
if (methods[0] is PbeMethod)
{
PbeMethod m = (PbeMethod)methods[0];
key = m.GetKey();
}
else
{
key = PgpUtilities.MakeRandomKey(defAlgorithm, rand);
byte[] sessionInfo = CreateSessionInfo(defAlgorithm, key);
PubMethod m = (PubMethod)methods[0];
try
{
m.AddSessionInfo(sessionInfo, rand);
}
catch (Exception e)
{
throw new PgpException("exception encrypting session key", e);
}
}
pOut.WritePacket((ContainedPacket)methods[0]);
}
else // multiple methods
{
key = PgpUtilities.MakeRandomKey(defAlgorithm, rand);
byte[] sessionInfo = CreateSessionInfo(defAlgorithm, key);
for (int i = 0; i != methods.Count; i++)
{
EncMethod m = (EncMethod)methods[i];
try
{
m.AddSessionInfo(sessionInfo, rand);
}
catch (Exception e)
{
throw new PgpException("exception encrypting session key", e);
}
pOut.WritePacket(m);
}
}
string cName = PgpUtilities.GetSymmetricCipherName(defAlgorithm);
if (cName == null)
{
throw new PgpException("null cipher specified");
}
try
{
if (withIntegrityPacket)
{
cName += "/CFB/NoPadding";
}
else
{
cName += "/OpenPGPCFB/NoPadding";
}
c = CipherUtilities.GetCipher(cName);
// TODO Confirm the IV should be all zero bytes (not inLineIv - see below)
byte[] iv = new byte[c.GetBlockSize()];
c.Init(true, new ParametersWithRandom(new ParametersWithIV(key, iv), rand));
if (buffer == null)
{
//
// we have to Add block size + 2 for the Generated IV and + 1 + 22 if integrity protected
//
if (withIntegrityPacket)
{
pOut = new BcpgOutputStream(outStr, PacketTag.SymmetricEncryptedIntegrityProtected, length + c.GetBlockSize() + 2 + 1 + 22);
pOut.WriteByte(1); // version number
}
else
{
pOut = new BcpgOutputStream(outStr, PacketTag.SymmetricKeyEncrypted, length + c.GetBlockSize() + 2, oldFormat);
}
}
else
{
if (withIntegrityPacket)
{
pOut = new BcpgOutputStream(outStr, PacketTag.SymmetricEncryptedIntegrityProtected, buffer);
pOut.WriteByte(1); // version number
}
else
{
pOut = new BcpgOutputStream(outStr, PacketTag.SymmetricKeyEncrypted, buffer);
}
}
int blockSize = c.GetBlockSize();
byte[] inLineIv = new byte[blockSize + 2];
rand.NextBytes(inLineIv, 0, blockSize);
Array.Copy(inLineIv, inLineIv.Length - 4, inLineIv, inLineIv.Length - 2, 2);
Stream myOut = cOut = new CipherStream(pOut, null, c);
if (withIntegrityPacket)
{
string digestName = PgpUtilities.GetDigestName(HashAlgorithmTag.Sha1);
IDigest digest = DigestUtilities.GetDigest(digestName);
myOut = digestOut = new DigestStream(myOut, null, digest);
}
myOut.Write(inLineIv, 0, inLineIv.Length);
return new WrappedGeneratorStream(this, myOut);
}
catch (Exception e)
{
throw new PgpException("Exception creating cipher", e);
}
}