public void Encrypt(IVocabularyProvider data, string what, Stream writer)
{
int overhead = 0;
long padding = writer.Position;
var rnd = new Random();
using (var briter = new BinaryWriter(writer, Encoding.Default, true))
{
foreach (char t in what)
{
for (int j = 0; j < 4; j++)
{
var ch = (ushort)(t & 0xF << 4 * j ^ data.Next());
briter.Write(ch);
}
if (t % 3 == 0)
{
briter.Write((short)rnd.Next(1023, 65535));
overhead++;
}
if (t % 2 == 0)
{
briter.Write((short)rnd.Next(1023, 65535));
overhead++;
}
}
}
writer.SetLength(padding + what.Length * 8 + overhead * 2);
}
public string Decrypt(IVocabularyProvider data, Stream reader)
{
int overhead = 0;
var builder = new StringBuilder();
long readerLength = reader.Length, streamLength = readerLength - reader.Position;
using (var breader = new BinaryReader(reader, Encoding.Default, true))
{
while (builder.Length < (streamLength - overhead * 2) / 8 && readerLength >= reader.Position + 8)
{
char x = default;
for (int j = 0; j < 4; j++)
{
var z = breader.ReadInt16();
var y = (char)(z ^ data.Next());
x |= y;
}
if (x % 3 == 0 && readerLength >= reader.Position + 2)
{
breader.ReadInt16();
overhead++;
}
if (x % 2 == 0 && readerLength >= reader.Position + 2)
{
breader.ReadInt16();
overhead++;
}
builder.Append(x);
}
}
return(builder.ToString());
}
private static CryptoDataV2 CheckCryptoData(IVocabularyProvider data)
{
if (!(data is CryptoDataV2 datav2))
{
throw new Exception("CryptorV2 expects CryptoDataV2 or later version as IVocabularyProvider");
}
return(datav2);
}
public static string Decrypt(IVocabularyProvider data, Stream reader)
{
foreach (var cryptor in Cryptors)
{
if (cryptor.CanDecrypt(reader))
{
return(cryptor.Decrypt(data, reader));
}
}
return(null);
}
public virtual string Decrypt(IVocabularyProvider data, Stream reader)
{
var offset = (reader.ReadByte() ^ data.Next()) & 0xFF;
reader.Position = offset;
for (int i = 0; i < (offset - (Magic.Length + 1) & 0xF); i++)
{
data.Next();
}
return(LegacyCryptor.Singleton.Decrypt(data, reader));
}
public virtual void Encrypt(IVocabularyProvider data, string what, Stream writer)
{
writer.Write(Magic, 0, Magic.Length);
var rnd = new Random();
var garbageCount = rnd.Next(10, 250);
var totalPadding = (byte)((garbageCount + Magic.Length + 1 ^ data.Next()) & 0xFF);
var buffer = new byte[garbageCount + 1];
rnd.NextBytes(buffer);
buffer[0] = totalPadding;
writer.Write(buffer, 0, buffer.Length);
for (int i = 0; i < (garbageCount & 0xF); i++)
{
data.Next();
}
LegacyCryptor.Singleton.Encrypt(data, what, writer);
}
public static void Encrypt(IVocabularyProvider data, string what, Stream writer)
{
Cryptors[0].Encrypt(data, what, writer);
}
public override void Encrypt(IVocabularyProvider data, string what, Stream writer)
{
base.Encrypt(CheckCryptoData(data).UpgradeToV2(), what, writer);
}
public override string Decrypt(IVocabularyProvider data, Stream reader)
{
return(base.Decrypt(CheckCryptoData(data).UpgradeToV2(), reader));
}
