private void LookForHeaderBlock()
{
byte[] lengthBytes = new byte[sizeof(Int32)];
if (!_inputStream.ReadExact(lengthBytes))
{
CurrentItemType = AxCryptItemType.EndOfStream;
return;
}
Int32 headerBlockLength = BitConverter.ToInt32(lengthBytes, 0) - 5;
if (headerBlockLength < 0 || headerBlockLength > 0xfffff)
{
throw new FileFormatException("Invalid headerBlockLength {0}".InvariantFormat(headerBlockLength), ErrorStatus.FileFormatError);
}
int blockType = _inputStream.ReadByte();
if (blockType > 127)
{
throw new FileFormatException("Invalid block type {0}".InvariantFormat(blockType), ErrorStatus.FileFormatError);
}
HeaderBlockType headerBlockType = (HeaderBlockType)blockType;
byte[] dataBLock = new byte[headerBlockLength];
if (!_inputStream.ReadExact(dataBLock))
{
CurrentItemType = AxCryptItemType.EndOfStream;
return;
}
ParseHeaderBlock(headerBlockType, dataBLock);
DataHeaderBlock dataHeaderBlock = CurrentHeaderBlock as DataHeaderBlock;
if (dataHeaderBlock != null)
{
CurrentItemType = AxCryptItemType.Data;
}
}
private void WriteInternal(Stream cipherStream, Stream hmacStream)
{
cipherStream.Position = 0;
AxCrypt1Guid.Write(cipherStream);
PreambleHeaderBlock preambleHaderBlock = FindHeaderBlock <PreambleHeaderBlock>();
preambleHaderBlock.Write(cipherStream);
foreach (HeaderBlock headerBlock in _headerBlocks)
{
if (headerBlock is DataHeaderBlock)
{
continue;
}
if (headerBlock is PreambleHeaderBlock)
{
continue;
}
headerBlock.Write(hmacStream);
}
DataHeaderBlock dataHeaderBlock = FindHeaderBlock <DataHeaderBlock>();
dataHeaderBlock.Write(hmacStream);
}
private void ParseHeaderBlock(HeaderBlockType headerBlockType, byte[] dataBlock)
{
bool isFirst = CurrentItemType == AxCryptItemType.MagicGuid;
CurrentItemType = AxCryptItemType.HeaderBlock;
if (headerBlockType == HeaderBlockType.Preamble)
{
if (!isFirst)
{
throw new FileFormatException("Preamble can only be first.", ErrorStatus.FileFormatError);
}
CurrentHeaderBlock = new PreambleHeaderBlock(dataBlock);
_sendDataToHmacStream = true;
return;
}
else
{
if (isFirst)
{
throw new FileFormatException("Preamble must be first.", ErrorStatus.FileFormatError);
}
}
switch (headerBlockType)
{
case HeaderBlockType.Version:
CurrentHeaderBlock = new VersionHeaderBlock(dataBlock);
break;
case HeaderBlockType.KeyWrap1:
CurrentHeaderBlock = new KeyWrap1HeaderBlock(dataBlock);
break;
case HeaderBlockType.KeyWrap2:
CurrentHeaderBlock = new KeyWrap2HeaderBlock(dataBlock);
break;
case HeaderBlockType.IdTag:
CurrentHeaderBlock = new IdTagHeaderBlock(dataBlock);
break;
case HeaderBlockType.Data:
CurrentHeaderBlock = new DataHeaderBlock(dataBlock);
break;
case HeaderBlockType.FileNameInfo:
CurrentHeaderBlock = new FileNameInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.EncryptionInfo:
CurrentHeaderBlock = new EncryptionInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.CompressionInfo:
CurrentHeaderBlock = new CompressionInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.FileInfo:
CurrentHeaderBlock = new FileInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.Compression:
CurrentHeaderBlock = new CompressionHeaderBlock(dataBlock);
break;
case HeaderBlockType.UnicodeFileNameInfo:
CurrentHeaderBlock = new UnicodeFileNameInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.Encrypted:
case HeaderBlockType.None:
case HeaderBlockType.Any:
throw new FileFormatException("Illegal header block type.", ErrorStatus.FileFormatError);
default:
CurrentHeaderBlock = new UnrecognizedHeaderBlock(headerBlockType, dataBlock);
break;
}
if (_sendDataToHmacStream)
{
CurrentHeaderBlock.Write(_hmacBufferStream);
}
return;
}
private void ParseHeaderBlock(HeaderBlockType headerBlockType, byte[] dataBlock)
{
bool isFirst = CurrentItemType == AxCryptItemType.MagicGuid;
CurrentItemType = AxCryptItemType.HeaderBlock;
if (headerBlockType == HeaderBlockType.Preamble)
{
if (!isFirst)
{
throw new FileFormatException("Preamble can only be first.", ErrorStatus.FileFormatError);
}
CurrentHeaderBlock = new PreambleHeaderBlock(dataBlock);
_sendDataToHmacStream = true;
return;
}
else
{
if (isFirst)
{
throw new FileFormatException("Preamble must be first.", ErrorStatus.FileFormatError);
}
}
switch (headerBlockType)
{
case HeaderBlockType.Version:
CurrentHeaderBlock = new VersionHeaderBlock(dataBlock);
break;
case HeaderBlockType.KeyWrap1:
CurrentHeaderBlock = new KeyWrap1HeaderBlock(dataBlock);
break;
case HeaderBlockType.KeyWrap2:
CurrentHeaderBlock = new KeyWrap2HeaderBlock(dataBlock);
break;
case HeaderBlockType.IdTag:
CurrentHeaderBlock = new IdTagHeaderBlock(dataBlock);
break;
case HeaderBlockType.Data:
CurrentHeaderBlock = new DataHeaderBlock(dataBlock);
break;
case HeaderBlockType.FileNameInfo:
CurrentHeaderBlock = new FileNameInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.EncryptionInfo:
CurrentHeaderBlock = new EncryptionInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.CompressionInfo:
CurrentHeaderBlock = new CompressionInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.FileInfo:
CurrentHeaderBlock = new FileInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.Compression:
CurrentHeaderBlock = new CompressionHeaderBlock(dataBlock);
break;
case HeaderBlockType.UnicodeFileNameInfo:
CurrentHeaderBlock = new UnicodeFileNameInfoHeaderBlock(dataBlock);
break;
case HeaderBlockType.Encrypted:
case HeaderBlockType.None:
case HeaderBlockType.Any:
throw new FileFormatException("Illegal header block type.", ErrorStatus.FileFormatError);
default:
CurrentHeaderBlock = new UnrecognizedHeaderBlock(headerBlockType, dataBlock);
break;
}
if (_sendDataToHmacStream)
{
CurrentHeaderBlock.Write(_hmacBufferStream);
}
return;
}
