static public void Decrypt(Stream source, Stream target, byte[] key, Bemani2DXEncryptionType type)
{
BinaryReader reader = new BinaryReader(source);
BinaryWriter writer = new BinaryWriter(target);
byte[] lastBlock = { 0, 0, 0, 0, 0, 0, 0, 0 };
byte[] currentBlock = { 0, 0, 0, 0, 0, 0, 0, 0 };
while (source.Position < source.Length)
{
byte[] block = reader.ReadBytes(8);
Array.Copy(block, currentBlock, 8);
// xor with key 0
for (int i = 0; i < 8; i++)
{
block[i] ^= key[i];
}
// manipulation
DecryptCycle(block);
// swap first half with second half
for (int i = 0; i < 4; i++)
{
byte swap = block[i];
block[i] = block[i + 4];
block[i + 4] = swap;
}
if (type == Bemani2DXEncryptionType.Standard)
{
// xor with key 1
for (int i = 0; i < 8; i++)
{
block[i] ^= key[8 + i];
}
// manipulation
DecryptCycle(block);
// xor with key 2
for (int i = 0; i < 8; i++)
{
block[i] ^= key[16 + i];
}
}
// xor with previous state
for (int i = 0; i < 8; i++)
{
block[i] ^= lastBlock[i];
}
// output
writer.Write(block);
Array.Copy(currentBlock, lastBlock, 8);
}
}
public static void Decrypt(Stream source, Stream target, byte[] key, Bemani2DXEncryptionType type)
{
BinaryReader reader = new BinaryReader(source);
BinaryWriter writer = new BinaryWriter(target);
byte[] lastBlock = {0, 0, 0, 0, 0, 0, 0, 0 };
byte[] currentBlock = { 0, 0, 0, 0, 0, 0, 0, 0 };
while (source.Position < source.Length)
{
byte[] block = reader.ReadBytes(8);
Array.Copy(block, currentBlock, 8);
// xor with key 0
for (int i = 0; i < 8; i++)
block[i] ^= key[i];
// manipulation
DecryptCycle(block);
// swap first half with second half
for (int i = 0; i < 4; i++)
{
byte swap = block[i];
block[i] = block[i + 4];
block[i + 4] = swap;
}
if (type == Bemani2DXEncryptionType.Standard)
{
// xor with key 1
for (int i = 0; i < 8; i++)
block[i] ^= key[8 + i];
// manipulation
DecryptCycle(block);
// xor with key 2
for (int i = 0; i < 8; i++)
block[i] ^= key[16 + i];
}
// xor with previous state
for (int i = 0; i < 8; i++)
block[i] ^= lastBlock[i];
// output
writer.Write(block);
Array.Copy(currentBlock, lastBlock, 8);
}
}
public static void Encrypt(Stream source, Stream target, byte[] key, Bemani2DXEncryptionType type)
{
}
static public Bemani2DX Read(Stream source)
{
Bemani2DX result = new Bemani2DX();
BinaryReader reader = new BinaryReader(source);
byte[] key = new byte[] { };
Bemani2DXEncryptionType encType = Bemani2DXEncryptionType.Standard;
string headerID = new string(reader.ReadChars(4));
switch (headerID)
{
case @"%eNc":
result.Type = Bemani2DXType.IIDX9;
key = Bemani2DXEncryptionKeys.IIDX9;
encType = Bemani2DXEncryptionType.Standard;
break;
case @"%e10":
result.Type = Bemani2DXType.IIDX10;
key = Bemani2DXEncryptionKeys.IIDX10;
encType = Bemani2DXEncryptionType.Standard;
break;
case @"%e11":
result.Type = Bemani2DXType.IIDX11;
key = Bemani2DXEncryptionKeys.IIDX11;
encType = Bemani2DXEncryptionType.Standard;
break;
case @"%e12":
result.Type = Bemani2DXType.IIDX12;
key = Bemani2DXEncryptionKeys.IIDX11;
encType = Bemani2DXEncryptionType.Partial;
break;
case @"%hid":
result.Type = Bemani2DXType.IIDXHID;
key = Bemani2DXEncryptionKeys.IIDX11;
encType = Bemani2DXEncryptionType.Partial;
break;
case @"%iO0":
result.Type = Bemani2DXType.IIDX16;
key = Bemani2DXEncryptionKeys.IIDX16;
encType = Bemani2DXEncryptionType.Standard;
break;
default:
result.Type = Bemani2DXType.Unencrypted;
source.Position -= 4;
break;
}
if (result.Type != Bemani2DXType.Unencrypted)
{
MemoryStream decodedData = new MemoryStream();
int filelength = reader.ReadInt32();
int fileExtraBytes = (8 - (filelength % 8)) % 8;
byte[] data = reader.ReadBytes(filelength + fileExtraBytes);
using (MemoryStream encodedDataMem = new MemoryStream(data))
{
Bemani2DXEncryption.Decrypt(encodedDataMem, decodedData, key, encType);
}
decodedData.Position = 0;
reader = new BinaryReader(decodedData);
}
// header length is at 0x10
// sample count is at 0x14
// offset list starts at 0x48
reader.BaseStream.Position = 0x10;
int headerLength = reader.ReadInt32();
int sampleCount = reader.ReadInt32();
long[] sampleOffset = new long[sampleCount];
reader.BaseStream.Position = 0x48;
for (int i = 0; i < sampleCount; i++)
{
sampleOffset[i] = reader.ReadInt32();
}
for (int i = 0; i < sampleCount; i++)
{
reader.BaseStream.Position = sampleOffset[i];
result.sounds.Add(Bemani2DXSound.Read(reader.BaseStream));
}
return(result);
}
static public void Encrypt(Stream source, Stream target, byte[] key, Bemani2DXEncryptionType type)
{
}
