private static Stream DecryptStream(TOle2File DataStream, TEncryptionParameters EncParams, TEncryptionKey Key)
{
DataStream.SelectStream(XlsxConsts.ContentString);
byte[] EncryptedSize = new byte[8];
DataStream.Read(EncryptedSize, EncryptedSize.Length);
AesManaged Engine = null;
ICryptoTransform Decryptor = null;
try
{
Engine = TEncryptionUtils.CreateEngine(EncParams);
if (!Key.VariableIV)
{
Decryptor = Engine.CreateDecryptor(Key.Key, Key.IV);
}
return(new TXlsxCryptoStreamReader(DataStream, BitOps.GetCardinal(EncryptedSize, 0), Engine, Decryptor, Key));
}
catch
{
if (Engine != null)
{
((IDisposable)Engine).Dispose();
}
if (Decryptor != null)
{
Decryptor.Dispose();
}
throw;
}
}
private void FinishEncryption()
{
TEncryptionParameters EncParams = GetEncryptionParams(Protection);
AesManaged EncEngine = TEncryptionUtils.CreateEngine(EncParams);
TAgileEncryptionKey DataKey = TAgileEncryptionKey.CreateForWriting(null, EncEngine.KeySize / 8);
DataKey.Key = TEncryptionUtils.GetRandom(DataKey.KeySizeInBytes);
TAgileEncryptionKey KeyKey = TAgileEncryptionKey.CreateForWriting(Protection.OpenPassword, EncEngine.KeySize / 8);
byte[] WorkLen = new byte[8];
BitOps.SetCardinal(WorkLen, 0, WorkingStream.Length - WorkStreamZeroPos);
EncryptStream(EncEngine, DataKey, WorkLen);
using (MemoryStream ms = new MemoryStream())
{
using (TOle2File Ole2File = new TOle2File(GetEmptyEncryptedFile()))
{
Ole2File.PrepareForWrite(ms, XlsxConsts.EncryptionInfoString, new string[0]);
CreateInfoStream(Ole2File, EncEngine, EncParams, KeyKey, DataKey);
}
ms.Position = 0;
using (TOle2File Ole2File = new TOle2File(ms))
{
Ole2File.PrepareForWrite(TargetStream, XlsxConsts.ContentString, new string[0]);
WorkingStream.Position = 0;
TEncryptionUtils.CopyStream(WorkingStream, Ole2File);
}
}
}
internal override bool VerifyPass(string Password, TEncryptionParameters EncParams, TEncryptionKey Key)
{
if (!base.VerifyPass(Password, EncParams, Key))
{
return(false);
}
Key.CalcKey(TStandardEncryptionKey.BlockKey, null);
byte[] DecriptedVerifier;
byte[] DecriptedVerifierHash;
using (AesManaged Engine = TEncryptionUtils.CreateEngine(EncParams))
{
using (ICryptoTransform Decryptor = Engine.CreateDecryptor(Key.Key, Key.IV))
{
DecriptedVerifier = DecryptBytes(EncryptedVerifier, Decryptor, -1);
DecriptedVerifierHash = DecryptBytes(EncryptedVerifierHash, Decryptor, -1);
}
}
using (HashAlgorithm hasher = TEncryptionKey.CreateHasher())
{
byte[] DecriptedVerifierHash2 = hasher.ComputeHash(DecriptedVerifier);
if (!FlxUtils.CompareMem(DecriptedVerifierHash, 0, DecriptedVerifierHash2, 0, VerifierHashSizeBytes))
{
return(false);
}
}
return(true);
}
private static byte[] GetBytesFromCryptoStream(CryptoStream cs, int MaxSize)
{
using (MemoryStream ms = new MemoryStream()) //not the most efficient code in the world, but should be used for small things
{
TEncryptionUtils.CopyStream(cs, ms, MaxSize);
return(ms.ToArray());
}
}
protected override byte[] DeriveIV(HashAlgorithm hasher, byte[] BlockKey)
{
byte[] ResultHash = Salt;
if (BlockKey != null)
{
ResultHash = hasher.ComputeHash(Concat(Salt, BlockKey));
}
return(TEncryptionUtils.PadArray(ResultHash, BlockSize, 0x36));
}
public static TAgileEncryptionKey CreateForWriting(string aPassword, int KeySizeInBytes)
{
const int SaltSize = 16;
TAgileEncryptionKey Result = new TAgileEncryptionKey();
Result.SpinCount = 100000;
Result.BlockSize = 16;
Result.KeySizeInBytes = KeySizeInBytes;
Result.Salt = TEncryptionUtils.GetRandom(SaltSize);
if (aPassword != null)
{
Result.Password = Encoding.Unicode.GetBytes(aPassword);
Result.PreCalcKey();
}
return(Result);
}
internal override bool VerifyPass(string Password, TEncryptionParameters EncParams, TEncryptionKey Key)
{
if (!base.VerifyPass(Password, EncParams, Key))
{
return(false);
}
using (AesManaged Engine = TEncryptionUtils.CreateEngine(EncParams))
{
byte[] DecriptedVerifierHashInput;
Key.CalcKey(TAgileEncryptionKey.VerifierHashInputBlockKey, null);
using (ICryptoTransform Decryptor = Engine.CreateDecryptor(Key.Key, Key.IV))
{
DecriptedVerifierHashInput = DecryptBytes(EncryptedVerifierHashInput, Decryptor, Key.Salt.Length); //this is the value padded to a blocksize multiple. We want only the Salt.Length initial bytes.
DecriptedVerifierHashInput = Key.Hash(DecriptedVerifierHashInput);
}
byte[] DecriptedVerifierHashValue;
Key.CalcKey(TAgileEncryptionKey.VerifierHashValueBlockKey, null);
using (ICryptoTransform Decryptor = Engine.CreateDecryptor(Key.Key, Key.IV))
{
DecriptedVerifierHashValue = DecryptBytes(EncryptedVerifierHashValue, Decryptor, DecriptedVerifierHashInput.Length); //this is the 20 byte value of the hash + 12 "0" so it goes up to 32. (32 is 2*blocksize)
}
if (!FlxUtils.CompareMem(DecriptedVerifierHashValue, DecriptedVerifierHashInput))
{
return(false);
}
byte[] DecriptedKeyValue;
Key.CalcKey(TAgileEncryptionKey.VerifierKeyValueBlockKey, null);
using (ICryptoTransform Decryptor = Engine.CreateDecryptor(Key.Key, Key.IV))
{
DecriptedKeyValue = DecryptBytes(EncryptedKeyValue, Decryptor, Key.KeySizeInBytes);
}
Key.Key = DecriptedKeyValue;
}
return(true);
}
protected override byte[] DeriveKey(HashAlgorithm hasher, byte[] hfinal)
{
return(TEncryptionUtils.PadArray(hfinal, KeySizeInBytes, 0x36));
}
private byte[] GetInfoStreamXml(AesManaged EncEngine, TEncryptionParameters EncParams, TAgileEncryptionKey KeyKey, TAgileEncryptionKey DataKey)
{
const string KeyEncryptorPasswordNamespace = "http://schemas.microsoft.com/office/2006/keyEncryptor/password";
using (MemoryStream ms = new MemoryStream())
{
XmlWriterSettings Settings = new XmlWriterSettings();
Settings.Encoding = new System.Text.UTF8Encoding(false);
using (XmlWriter xml = XmlWriter.Create(ms, Settings))
{
xml.WriteStartDocument(true);
xml.WriteStartElement("encryption", "http://schemas.microsoft.com/office/2006/encryption");
xml.WriteAttributeString("xmlns", "p", null, KeyEncryptorPasswordNamespace);
xml.WriteStartElement("keyData");
WriteAgileCipherParams(xml, EncParams, DataKey);
xml.WriteEndElement();
xml.WriteStartElement("dataIntegrity");
byte[] HMacKeyBlockKey = new byte[] { 0x5f, 0xb2, 0xad, 0x01, 0x0c, 0xb9, 0xe1, 0xf6 };
DataKey.CalcDataIV(HMacKeyBlockKey);
byte[] HMacKey = TEncryptionUtils.GetRandom((int)DataKey.HashSizeBytes());
using (ICryptoTransform Encryptor = EncEngine.CreateEncryptor(DataKey.Key, DataKey.IV))
{
byte[] EncryptedHMacKey = TAgileEncryptionVerifier.EncryptBytes(HMacKey, Encryptor, DataKey.BlockSize);
xml.WriteAttributeString("encryptedHmacKey", Convert.ToBase64String(EncryptedHMacKey));
}
HMAC HMacCalc = new HMACSHA1(HMacKey);
WorkingStream.Position = 0;
byte[] HMac = HMacCalc.ComputeHash(WorkingStream);
byte[] HMacValBlockKey = new byte[] { 0xa0, 0x67, 0x7f, 0x02, 0xb2, 0x2c, 0x84, 0x33 };
DataKey.CalcDataIV(HMacValBlockKey);
using (ICryptoTransform Encryptor = EncEngine.CreateEncryptor(DataKey.Key, DataKey.IV))
{
byte[] EncryptedHMacValue = TAgileEncryptionVerifier.EncryptBytes(HMac, Encryptor, DataKey.BlockSize);
xml.WriteAttributeString("encryptedHmacValue", Convert.ToBase64String(EncryptedHMacValue));
}
xml.WriteEndElement();
xml.WriteStartElement("keyEncryptors");
xml.WriteStartElement("keyEncryptor");
xml.WriteAttributeString("uri", KeyEncryptorPasswordNamespace);
xml.WriteStartElement("encryptedKey", KeyEncryptorPasswordNamespace);
xml.WriteAttributeString("spinCount", Convert.ToString(KeyKey.SpinCount, CultureInfo.InvariantCulture));
WriteAgileCipherParams(xml, EncParams, KeyKey);
byte[] RandData = TEncryptionUtils.GetRandom(KeyKey.Salt.Length);
KeyKey.CalcKey(TAgileEncryptionKey.VerifierHashInputBlockKey, null);
using (ICryptoTransform Encryptor = EncEngine.CreateEncryptor(KeyKey.Key, KeyKey.IV))
{
byte[] EncryptedVerifierHashInput = TAgileEncryptionVerifier.EncryptBytes(RandData, Encryptor, KeyKey.BlockSize);
xml.WriteAttributeString("encryptedVerifierHashInput", Convert.ToBase64String(EncryptedVerifierHashInput));
}
KeyKey.CalcKey(TAgileEncryptionKey.VerifierHashValueBlockKey, null);
using (ICryptoTransform Encryptor = EncEngine.CreateEncryptor(KeyKey.Key, KeyKey.IV))
{
byte[] EncryptedVerifierHashValue = TAgileEncryptionVerifier.EncryptBytes(KeyKey.Hash(RandData), Encryptor, KeyKey.BlockSize);
xml.WriteAttributeString("encryptedVerifierHashValue", Convert.ToBase64String(EncryptedVerifierHashValue));
}
KeyKey.CalcKey(TAgileEncryptionKey.VerifierKeyValueBlockKey, null);
using (ICryptoTransform Encryptor = EncEngine.CreateEncryptor(KeyKey.Key, KeyKey.IV))
{
byte[] EncryptedKeyValue = TAgileEncryptionVerifier.EncryptBytes(DataKey.Key, Encryptor, KeyKey.BlockSize);
xml.WriteAttributeString("encryptedKeyValue", Convert.ToBase64String(EncryptedKeyValue));
}
xml.WriteEndElement();
xml.WriteEndElement();
xml.WriteEndElement();
xml.WriteEndElement();
xml.WriteEndDocument();
}
return(ms.ToArray());
}
}
