/// <summary>
/// Read the package from the OLE document and decrypt it using the supplied password
/// </summary>
/// <param name="stream">The memory stream. </param>
/// <param name="encryption">The encryption object from the Package</param>
/// <returns></returns>
internal MemoryStream DecryptPackage(MemoryStream stream, ExcelEncryption encryption)
{
//Create the lockBytes object.
ILockBytes lb = GetLockbyte(stream);
MemoryStream ret = null;
if (StgIsStorageILockBytes(lb) == 0)
{
IStorage storage = null;
if (StgOpenStorageOnILockBytes(
lb,
null,
STGM.DIRECT | STGM.READ | STGM.SHARE_EXCLUSIVE,
IntPtr.Zero,
0,
out storage) == 0)
{
ret = GetStreamFromPackage(storage, encryption);
}
Marshal.ReleaseComObject(storage);
}
else
{
throw (new InvalidDataException("The stream is not an encrypted package"));
}
Marshal.ReleaseComObject(lb);
return(ret);
}
/// <summary>
/// Read the package from the OLE document and decrypt it using the supplied password
/// </summary>
/// <param name="fi">The file</param>
/// <param name="encryption"></param>
/// <returns></returns>
internal MemoryStream DecryptPackage(FileInfo fi, ExcelEncryption encryption)
{
MemoryStream ret = null;
if (StgIsStorageFile(fi.FullName) == 0)
{
IStorage storage = null;
if (StgOpenStorage(
fi.FullName,
null,
STGM.DIRECT | STGM.READ | STGM.SHARE_EXCLUSIVE,
IntPtr.Zero,
0,
out storage) == 0)
{
ret = GetStreamFromPackage(storage, encryption);
Marshal.ReleaseComObject(storage);
}
}
else
{
throw(new InvalidDataException(string.Format("File {0} is not an encrypted package", fi.FullName)));
}
return(ret);
}
private MemoryStream GetStreamFromPackage(IStorage storage, ExcelEncryption encryption)
{
MemoryStream ret = null;
comTypes.STATSTG statstg;
storage.Stat(out statstg, (uint)STATFLAG.STATFLAG_DEFAULT);
IEnumSTATSTG pIEnumStatStg = null;
storage.EnumElements(0, IntPtr.Zero, 0, out pIEnumStatStg);
comTypes.STATSTG[] regelt = { statstg };
uint fetched = 0;
uint res = pIEnumStatStg.Next(1, regelt, out fetched);
//if (regelt[0].pwcsName == "DataSpaces")
//{
// PrintStorage(storage, regelt[0],"");
//}
if (res == 0)
{
byte[] data;
EncryptionInfo encryptionInfo = null;
while (res != 1)
{
switch (statstg.pwcsName)
{
case "EncryptionInfo":
data = GetOleStream(storage, statstg);
//File.WriteAllBytes(@"c:\temp\EncInfo1.bin", data);
encryptionInfo = new EncryptionInfo();
encryptionInfo.ReadBinary(data);
encryption.Algorithm = encryptionInfo.Header.AlgID == AlgorithmID.AES128 ?
EncryptionAlgorithm.AES128 :
encryptionInfo.Header.AlgID == AlgorithmID.AES192 ?
EncryptionAlgorithm.AES192 :
EncryptionAlgorithm.AES256;
break;
case "EncryptedPackage":
data = GetOleStream(storage, statstg);
ret = DecryptDocument(data, encryptionInfo, encryption.Password);
break;
}
if ((res = pIEnumStatStg.Next(1, regelt, out fetched)) != 1)
{
statstg = regelt[0];
}
}
}
Marshal.ReleaseComObject(pIEnumStatStg);
return(ret);
}
private MemoryStream GetStreamFromPackage(IStorage storage, ExcelEncryption encryption)
{
MemoryStream ret=null;
comTypes.STATSTG statstg;
storage.Stat(out statstg, (uint)STATFLAG.STATFLAG_DEFAULT);
IEnumSTATSTG pIEnumStatStg = null;
storage.EnumElements(0, IntPtr.Zero, 0, out pIEnumStatStg);
comTypes.STATSTG[] regelt = { statstg };
uint fetched = 0;
uint res = pIEnumStatStg.Next(1, regelt, out fetched);
//if (regelt[0].pwcsName == "DataSpaces")
//{
// PrintStorage(storage, regelt[0],"");
//}
if (res == 0)
{
byte[] data;
EncryptionInfo encryptionInfo = null;
while (res != 1)
{
switch (statstg.pwcsName)
{
case "EncryptionInfo":
data = GetOleStream(storage, statstg);
//File.WriteAllBytes(@"c:\temp\EncInfo1.bin", data);
encryptionInfo = new EncryptionInfo();
encryptionInfo.ReadBinary(data);
encryption.Algorithm = encryptionInfo.Header.AlgID == AlgorithmID.AES128 ?
EncryptionAlgorithm.AES128 :
encryptionInfo.Header.AlgID == AlgorithmID.AES192 ?
EncryptionAlgorithm.AES192 :
EncryptionAlgorithm.AES256;
break;
case "EncryptedPackage":
data = GetOleStream(storage, statstg);
ret = DecryptDocument(data, encryptionInfo, encryption.Password);
break;
}
if ((res = pIEnumStatStg.Next(1, regelt, out fetched)) != 1)
{
statstg = regelt[0];
}
}
}
Marshal.ReleaseComObject(pIEnumStatStg);
return ret;
}
/// <summary>
/// Encrypts a package
/// </summary>
/// <param name="package">The package as a byte array</param>
/// <param name="encryption">The encryption info from the workbook</param>
/// <returns></returns>
internal MemoryStream EncryptPackage(byte[] package, ExcelEncryption encryption)
{
byte[] encryptionKey;
//Create the Encryption Info. This also returns the Encryptionkey
var encryptionInfo = CreateEncryptionInfo(encryption.Password,
encryption.Algorithm == EncryptionAlgorithm.AES128 ?
AlgorithmID.AES128 :
encryption.Algorithm == EncryptionAlgorithm.AES192 ?
AlgorithmID.AES192 :
AlgorithmID.AES256, out encryptionKey);
ILockBytes lb;
var iret = CreateILockBytesOnHGlobal(IntPtr.Zero, true, out lb);
IStorage storage = null;
MemoryStream ret = null;
//Create the document in-memory
if (StgCreateDocfileOnILockBytes(lb,
STGM.CREATE | STGM.READWRITE | STGM.SHARE_EXCLUSIVE | STGM.TRANSACTED,
0,
out storage)==0)
{
//First create the dataspace storage
CreateDataSpaces(storage);
//Create the Encryption info Stream
comTypes.IStream stream;
storage.CreateStream("EncryptionInfo", (uint)(STGM.CREATE | STGM.WRITE | STGM.DIRECT | STGM.SHARE_EXCLUSIVE), (uint)0, (uint)0, out stream);
byte[] ei=encryptionInfo.WriteBinary();
stream.Write(ei, ei.Length, IntPtr.Zero);
stream = null;
//Encrypt the package
byte[] encryptedPackage=EncryptData(encryptionKey, package, false);
storage.CreateStream("EncryptedPackage", (uint)(STGM.CREATE | STGM.WRITE | STGM.DIRECT | STGM.SHARE_EXCLUSIVE), (uint)0, (uint)0, out stream);
//Write Size here
MemoryStream ms = new MemoryStream();
BinaryWriter bw = new BinaryWriter(ms);
bw.Write((ulong)package.LongLength);
bw.Flush();
byte[] length = ms.ToArray();
//Write Encrypted data length first as an unsigned long
stream.Write(length, length.Length, IntPtr.Zero);
//And now the Encrypted data
stream.Write(encryptedPackage, encryptedPackage.Length, IntPtr.Zero);
stream = null;
storage.Commit(0);
lb.Flush();
//Now copy the unmanaged stream to a byte array --> memory stream
var statstg = new comTypes.STATSTG();
lb.Stat(out statstg, 0);
int size = (int)statstg.cbSize;
IntPtr buffer = Marshal.AllocHGlobal(size);
UIntPtr readSize;
byte[] pack=new byte[size];
lb.ReadAt(0, buffer, size, out readSize);
Marshal.Copy(buffer, pack, 0, size);
Marshal.FreeHGlobal(buffer);
ret = new MemoryStream();
ret.Write(pack, 0, size);
}
Marshal.ReleaseComObject(storage);
Marshal.ReleaseComObject(lb);
return ret;
}
/// <summary>
/// Read the package from the OLE document and decrypt it using the supplied password
/// </summary>
/// <param name="stream">The memory stream. </param>
/// <param name="encryption">The encryption object from the Package</param>
/// <returns></returns>
internal MemoryStream DecryptPackage(MemoryStream stream, ExcelEncryption encryption)
{
//Create the lockBytes object.
ILockBytes lb = GetLockbyte(stream);
MemoryStream ret = null;
if (StgIsStorageILockBytes(lb) == 0)
{
IStorage storage = null;
if (StgOpenStorageOnILockBytes(
lb,
null,
STGM.DIRECT | STGM.READ | STGM.SHARE_EXCLUSIVE,
IntPtr.Zero,
0,
out storage) == 0)
{
ret = GetStreamFromPackage(storage, encryption);
}
Marshal.ReleaseComObject(storage);
}
else
{
throw (new Exception("The stream is not an encrypted package"));
}
Marshal.ReleaseComObject(lb);
return ret;
}
/// <summary>
/// Read the package from the OLE document and decrypt it using the supplied password
/// </summary>
/// <param name="fi">The file</param>
/// <param name="encryption"></param>
/// <returns></returns>
internal MemoryStream DecryptPackage(FileInfo fi, ExcelEncryption encryption)
{
MemoryStream ret = null;
if (StgIsStorageFile(fi.FullName) == 0)
{
IStorage storage = null;
if (StgOpenStorage(
fi.FullName,
null,
STGM.DIRECT | STGM.READ | STGM.SHARE_EXCLUSIVE,
IntPtr.Zero,
0,
out storage) == 0)
{
ret = GetStreamFromPackage(storage, encryption);
Marshal.ReleaseComObject(storage);
}
}
else
{
throw(new Exception(string.Format("File {0} is not an encrypted package",fi.FullName)));
}
return ret;
}
/// <summary>
/// Encrypts a package
/// </summary>
/// <param name="package">The package as a byte array</param>
/// <param name="encryption">The encryption info from the workbook</param>
/// <returns></returns>
internal MemoryStream EncryptPackage(byte[] package, ExcelEncryption encryption)
{
byte[] encryptionKey;
//Create the Encryption Info. This also returns the Encryptionkey
var encryptionInfo = CreateEncryptionInfo(encryption.Password,
encryption.Algorithm == EncryptionAlgorithm.AES128 ?
AlgorithmID.AES128 :
encryption.Algorithm == EncryptionAlgorithm.AES192 ?
AlgorithmID.AES192 :
AlgorithmID.AES256, out encryptionKey);
ILockBytes lb;
var iret = CreateILockBytesOnHGlobal(IntPtr.Zero, true, out lb);
IStorage storage = null;
MemoryStream ret = null;
//Create the document in-memory
if (StgCreateDocfileOnILockBytes(lb,
STGM.CREATE | STGM.READWRITE | STGM.SHARE_EXCLUSIVE | STGM.TRANSACTED,
0,
out storage) == 0)
{
//First create the dataspace storage
CreateDataSpaces(storage);
//Create the Encryption info Stream
comTypes.IStream stream;
storage.CreateStream("EncryptionInfo", (uint)(STGM.CREATE | STGM.WRITE | STGM.DIRECT | STGM.SHARE_EXCLUSIVE), (uint)0, (uint)0, out stream);
byte[] ei = encryptionInfo.WriteBinary();
stream.Write(ei, ei.Length, IntPtr.Zero);
stream = null;
//Encrypt the package
byte[] encryptedPackage = EncryptData(encryptionKey, package, false);
storage.CreateStream("EncryptedPackage", (uint)(STGM.CREATE | STGM.WRITE | STGM.DIRECT | STGM.SHARE_EXCLUSIVE), (uint)0, (uint)0, out stream);
//Write Size here
MemoryStream ms = new MemoryStream();
BinaryWriter bw = new BinaryWriter(ms);
bw.Write((ulong)package.LongLength);
bw.Flush();
byte[] length = ms.ToArray();
//Write Encrypted data length first as an unsigned long
stream.Write(length, length.Length, IntPtr.Zero);
//And now the Encrypted data
stream.Write(encryptedPackage, encryptedPackage.Length, IntPtr.Zero);
stream = null;
storage.Commit(0);
lb.Flush();
//Now copy the unmanaged stream to a byte array --> memory stream
var statstg = new comTypes.STATSTG();
lb.Stat(out statstg, 0);
int size = (int)statstg.cbSize;
IntPtr buffer = Marshal.AllocHGlobal(size);
UIntPtr readSize;
byte[] pack = new byte[size];
lb.ReadAt(0, buffer, size, out readSize);
Marshal.Copy(buffer, pack, 0, size);
Marshal.FreeHGlobal(buffer);
ret = new MemoryStream();
ret.Write(pack, 0, size);
}
Marshal.ReleaseComObject(storage);
Marshal.ReleaseComObject(lb);
return(ret);
}
