/**
* Decrypt the Document-/SummaryInformation and other optionally streams.
* Opposed to other crypto modes, cryptoapi is record based and can't be used
* to stream-decrypt a whole file
*
* @see <a href="http://msdn.microsoft.com/en-us/library/dd943321(v=office.12).aspx">2.3.5.4 RC4 CryptoAPI Encrypted Summary Stream</a>
*/
public override InputStream GetDataStream(DirectoryNode dir)
{
NPOIFSFileSystem fsOut = new NPOIFSFileSystem();
DocumentNode es = (DocumentNode)dir.GetEntry("EncryptedSummary");
DocumentInputStream dis = dir.CreateDocumentInputStream(es);
MemoryStream bos = new MemoryStream();
IOUtils.Copy(dis, bos);
dis.Close();
SeekableMemoryStream sbis = new SeekableMemoryStream(bos.ToArray());
LittleEndianInputStream leis = new LittleEndianInputStream(sbis);
int streamDescriptorArrayOffset = (int)leis.ReadUInt();
int streamDescriptorArraySize = (int)leis.ReadUInt();
sbis.Seek(streamDescriptorArrayOffset - 8, SeekOrigin.Current);// sbis.Skip(streamDescriptorArrayOffset - 8);
sbis.SetBlock(0);
int encryptedStreamDescriptorCount = (int)leis.ReadUInt();
StreamDescriptorEntry[] entries = new StreamDescriptorEntry[encryptedStreamDescriptorCount];
for (int i = 0; i < encryptedStreamDescriptorCount; i++)
{
StreamDescriptorEntry entry = new StreamDescriptorEntry();
entries[i] = entry;
entry.streamOffset = (int)leis.ReadUInt();
entry.streamSize = (int)leis.ReadUInt();
entry.block = leis.ReadUShort();
int nameSize = leis.ReadUByte();
entry.flags = leis.ReadUByte();
bool IsStream = StreamDescriptorEntry.flagStream.IsSet(entry.flags);
entry.reserved2 = leis.ReadInt();
entry.streamName = StringUtil.ReadUnicodeLE(leis, nameSize);
leis.ReadShort();
Debug.Assert(entry.streamName.Length == nameSize);
}
foreach (StreamDescriptorEntry entry in entries)
{
sbis.Seek(entry.streamOffset);
sbis.SetBlock(entry.block);
Stream is1 = new BufferedStream(sbis, entry.streamSize);
fsOut.CreateDocument(is1, entry.streamName);
}
leis.Close();
sbis = null;
bos.Seek(0, SeekOrigin.Begin); //bos.Reset();
fsOut.WriteFileSystem(bos);
fsOut.Close();
_length = bos.Length;
ByteArrayInputStream bis = new ByteArrayInputStream(bos.ToArray());
throw new NotImplementedException("ByteArrayInputStream should be derived from InputStream");
}
/**
* Encrypt the Document-/SummaryInformation and other optionally streams.
* Opposed to other crypto modes, cryptoapi is record based and can't be used
* to stream-encrypt a whole file
*
* @see <a href="http://msdn.microsoft.com/en-us/library/dd943321(v=office.12).aspx">2.3.5.4 RC4 CryptoAPI Encrypted Summary Stream</a>
*/
public override OutputStream GetDataStream(DirectoryNode dir)
{
CipherByteArrayOutputStream bos = new CipherByteArrayOutputStream(this);
byte[] buf = new byte[8];
bos.Write(buf, 0, 8); // skip header
String[] entryNames =
{
SummaryInformation.DEFAULT_STREAM_NAME,
DocumentSummaryInformation.DEFAULT_STREAM_NAME
};
List <StreamDescriptorEntry> descList = new List <StreamDescriptorEntry>();
int block = 0;
foreach (String entryName in entryNames)
{
if (!dir.HasEntry(entryName))
{
continue;
}
StreamDescriptorEntry descEntry = new StreamDescriptorEntry();
descEntry.block = block;
descEntry.streamOffset = (int)bos.Length;
descEntry.streamName = entryName;
descEntry.flags = StreamDescriptorEntry.flagStream.SetValue(0, 1);
descEntry.reserved2 = 0;
bos.SetBlock(block);
DocumentInputStream dis = dir.CreateDocumentInputStream(entryName);
IOUtils.Copy(dis, bos);
dis.Close();
descEntry.streamSize = (int)(bos.Length - descEntry.streamOffset);
descList.Add(descEntry);
dir.GetEntry(entryName).Delete();
block++;
}
int streamDescriptorArrayOffset = (int)bos.Length;
bos.SetBlock(0);
LittleEndian.PutUInt(buf, 0, descList.Count);
bos.Write(buf, 0, 4);
foreach (StreamDescriptorEntry sde in descList)
{
LittleEndian.PutUInt(buf, 0, sde.streamOffset);
bos.Write(buf, 0, 4);
LittleEndian.PutUInt(buf, 0, sde.streamSize);
bos.Write(buf, 0, 4);
LittleEndian.PutUShort(buf, 0, sde.block);
bos.Write(buf, 0, 2);
LittleEndian.PutUByte(buf, 0, (short)sde.streamName.Length);
bos.Write(buf, 0, 1);
LittleEndian.PutUByte(buf, 0, (short)sde.flags);
bos.Write(buf, 0, 1);
LittleEndian.PutUInt(buf, 0, sde.reserved2);
bos.Write(buf, 0, 4);
byte[] nameBytes = StringUtil.GetToUnicodeLE(sde.streamName);
bos.Write(nameBytes, 0, nameBytes.Length);
LittleEndian.PutShort(buf, 0, (short)0); // null-termination
bos.Write(buf, 0, 2);
}
int savedSize = (int)bos.Length;
int streamDescriptorArraySize = savedSize - streamDescriptorArrayOffset;
LittleEndian.PutUInt(buf, 0, streamDescriptorArrayOffset);
LittleEndian.PutUInt(buf, 4, streamDescriptorArraySize);
bos.Reset();
bos.SetBlock(0);
bos.Write(buf, 0, 8);
bos.SetSize(savedSize);
dir.CreateDocument("EncryptedSummary", new MemoryStream(bos.GetBuf(), 0, savedSize));
DocumentSummaryInformation dsi = PropertySetFactory.NewDocumentSummaryInformation();
try
{
dsi.Write(dir, DocumentSummaryInformation.DEFAULT_STREAM_NAME);
}
catch (WritingNotSupportedException e)
{
throw new IOException(e.Message);
}
//return bos;
throw new NotImplementedException("CipherByteArrayOutputStream should be derived from OutputStream");
}