public static ICryptoTransform GetDecryptor(byte SymAlgo, byte[] IV, byte[] SessionKey)
{
if (!IsValidAlgoCode(SymAlgo))
{
throw new NotImplementedException("Algorithm not implemented");
}
int KeySize = SymmetricAlgorithmTypes.GetKeySize(SymAlgo);
int BlockSizeBits = SymmetricAlgorithmTypes.GetBlockSize(SymAlgo);
if (IV == null)
{
IV = new byte[BlockSizeBits / 8]; // Set to all zeros by default
}
RijndaelManaged aes = new RijndaelManaged
{
KeySize = KeySize,
BlockSize = BlockSizeBits,
FeedbackSize = BlockSizeBits,
Key = SessionKey,
IV = IV,
Mode = CipherMode.CFB,
Padding = PaddingMode.None
};
return(aes.CreateDecryptor());
}
public byte[] GetKey(string Password)
{
int KeySize = SymmetricAlgorithmTypes.GetKeySize(SymAlgo);
int DesiredBytes = (byte)(KeySize / 8);
HashAlgorithm HashAlgo = HashAlgorithmTypes.GetHashAlgoManaged(HashAlgorithm);
byte[] Key = GetSaltedIterated(HashAlgo, DesiredBytes, Salt, Encoding.ASCII.GetBytes(Password), ByteCount);
return(Key);
}
public override void Parse(TreeBuilder tree)
{
base.Parse(tree);
bool IsEncrypted = true;
tree.SetBookMark();
var S2K = new S2K
{
S2KUsage = tree.ReadByte()
};
if (S2K.S2KUsage == 254 || S2K.S2KUsage == 255)
{
S2K.SymAlgo = tree.ReadByte("Symmetric Algorithm", SymmetricAlgorithmTypes.Get);
byte S2KSpecifier = tree.ReadByte("S2K Specifier", S2KTypes.Get);
if (S2KSpecifier != S2KTypes.Salted && S2KSpecifier != S2KTypes.Simple && S2KSpecifier != S2KTypes.IteratedAndSalted)
{
//tree.AddCalculated("Invalid S2K", S2KSpecifier.ToString());
tree.AddCalculated("Unable to Process", S2KSpecifier.ToString(), ByteBlockType.CalculatedError);
return;
}
S2K.HashAlgorithm = tree.ReadByte("Hash Algorithm", HashAlgorithmTypes.Get);
if (S2KSpecifier == S2KTypes.Salted || S2KSpecifier == S2KTypes.IteratedAndSalted)
{
S2K.Salt = tree.ReadBytes("Salt", 8);
if (S2KSpecifier == S2KTypes.IteratedAndSalted)
{
byte CodedCount = tree.ReadByte("Coded Iteration");
S2K.ByteCount = (16 + (CodedCount & 15)) << ((CodedCount >> 4) + 6);
}
}
int BlockSizeBytes = SymmetricAlgorithmTypes.GetBlockSize(S2K.SymAlgo) / 8;
S2K.IV = tree.ReadBytes("IV", BlockSizeBytes);
}
else
{
byte SymAlgo = S2K.S2KUsage;
S2K.SymAlgo = SymAlgo;
if (SymAlgo != 0)
{
tree.GoToBookMark();
tree.ReadByte("Symmetric Algorithm", SymmetricAlgorithmTypes.Get);
int BlockSize = SymmetricAlgorithmTypes.GetBlockSize(SymAlgo) / 8;
S2K.IV = tree.ReadBytes("IV", BlockSize);
}
else
{
IsEncrypted = false;
}
}
PublicKeyAlgorithm.S2K = S2K;
if (IsEncrypted)
{
byte[] Encrypted = tree.ReadBytes("Encrypted Secret Key");
PublicKeyAlgorithm.EncryptedPrivateKey = Encrypted;
tree.CurrentBlock.ProcessBlock += ExtractPrivateKey;
SecretKeyNode = tree.CurrentBlock;
}
else
{
byte[] ClearBytes = tree.ReadBytes("Unencrypted Secret Key");
var SecBlockClear = PublicKeyAlgorithm.SetPrivate(ClearBytes);
tree.AddChild(PublicKeyAlgorithm.GetPrivateByteBlocks());
}
}
