private byte[] DecryptData(int dataSize, long dataRelativeOffset, long pkgEncryptedFileStartOffset, byte[] AesKey, Stream encrPKGReadStream, BinaryReader brEncrPKG)
{
int size = dataSize % 16;
if (size > 0)
{
size = ((dataSize / 16) + 1) * 16;
}
else
{
size = dataSize;
}
byte[] EncryptedData = new byte[size];
byte[] DecryptedData = new byte[size];
byte[] PKGFileKeyConsec = new byte[size];
byte[] PKGXorKeyConsec = new byte[size];
byte[] incPKGFileKey = new byte[PKGFileKey.Length];
Array.Copy(PKGFileKey, incPKGFileKey, PKGFileKey.Length);
encrPKGReadStream.Seek(dataRelativeOffset + pkgEncryptedFileStartOffset, SeekOrigin.Begin);
EncryptedData = brEncrPKG.ReadBytes(size);
for (int pos = 0; pos < dataRelativeOffset; pos += 16)
{
IncrementArray(ref incPKGFileKey, PKGFileKey.Length - 1);
}
for (int pos = 0; pos < size; pos += 16)
{
Array.Copy(incPKGFileKey, 0, PKGFileKeyConsec, pos, PKGFileKey.Length);
IncrementArray(ref incPKGFileKey, PKGFileKey.Length - 1);
}
//the incremented "file" key have to be encrypted with a "global AES key" to generate the "xor" key
//PSP uses CipherMode.ECB, PaddingMode.None that doesn't need IV
PKGXorKeyConsec = AESEngine.Encrypt(PKGFileKeyConsec, AesKey, AesKey, CipherMode.ECB, PaddingMode.None);
//XOR Decrypt and save every 16 bytes of data:
DecryptedData = XOREngine.XOR(EncryptedData, 0, PKGXorKeyConsec.Length, PKGXorKeyConsec);
return(DecryptedData);
}
private string DecryptPKGFile(string PKGFileName)
{
try
{
int moltiplicator = 65536;
byte[] EncryptedData = new byte[AesKey.Length * moltiplicator];
byte[] DecryptedData = new byte[AesKey.Length * moltiplicator];
byte[] PKGXorKey = new byte[AesKey.Length];
byte[] EncryptedFileStartOffset = new byte[4];
byte[] EncryptedFileLenght = new byte[4];
Stream PKGReadStream = new FileStream(PKGFileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
BinaryReader brPKG = new BinaryReader(PKGReadStream);
PKGReadStream.Seek(0x00, SeekOrigin.Begin);
byte[] pkgMagic = brPKG.ReadBytes(4);
if (pkgMagic[0x00] != 0x7F || pkgMagic[0x01] != 0x50 || pkgMagic[0x02] != 0x4B || pkgMagic[0x03] != 0x47)
{
txtResults.Text += "ERROR: Selected file isn't a Pkg file.";
SystemSounds.Beep.Play();
return(string.Empty);
}
//Finalized byte
PKGReadStream.Seek(0x04, SeekOrigin.Begin);
byte pkgFinalized = brPKG.ReadByte();
if (pkgFinalized != 0x80)
{
MessageBox.Show("Detected Debug PKG. Currently fixing tool. Please be patient");
SystemSounds.Beep.Play();
SystemSounds.Beep.Play();
}
//PKG Type PSP/PS3
PKGReadStream.Seek(0x07, SeekOrigin.Begin);
byte pkgType = brPKG.ReadByte();
switch (pkgType)
{
case 0x01:
//PS3
AesKey = PS3AesKey;
break;
case 0x02:
//PSP
AesKey = PSPAesKey;
break;
default:
txtResults.Text += "ERROR: Selected pkg isn't Valid.";
SystemSounds.Beep.Play();
return(string.Empty);
}
//0x24 Store the start Address of the encrypted file to decrypt
PKGReadStream.Seek(0x24, SeekOrigin.Begin);
EncryptedFileStartOffset = brPKG.ReadBytes((int)EncryptedFileStartOffset.Length);
Array.Reverse(EncryptedFileStartOffset);
uiEncryptedFileStartOffset = BitConverter.ToUInt32(EncryptedFileStartOffset, 0);
//0x1C Store the length of the whole pkg file
//0x2C Store the length of the encrypted file to decrypt
PKGReadStream.Seek(0x2C, SeekOrigin.Begin);
EncryptedFileLenght = brPKG.ReadBytes((int)EncryptedFileLenght.Length);
Array.Reverse(EncryptedFileLenght);
uint uiEncryptedFileLenght = BitConverter.ToUInt32(EncryptedFileLenght, 0);
//0x70 Store the PKG file Key.
PKGReadStream.Seek(0x70, SeekOrigin.Begin);
PKGFileKey = brPKG.ReadBytes(16);
byte[] incPKGFileKey = new byte[16];
Array.Copy(PKGFileKey, incPKGFileKey, PKGFileKey.Length);
//the "file" key at 0x70 have to be encrypted with a "global AES key" to generate the "xor" key
//PSP uses CipherMode.ECB, PaddingMode.None that doesn't need IV
PKGXorKey = AESEngine.Encrypt(PKGFileKey, AesKey, AesKey, CipherMode.ECB, PaddingMode.None);
// Pieces calculation
double division = (double)uiEncryptedFileLenght / (double)AesKey.Length;
UInt64 pieces = (UInt64)Math.Floor(division);
UInt64 mod = (UInt64)uiEncryptedFileLenght / (UInt64)AesKey.Length;
if (mod > 0)
{
pieces += 1;
}
if (File.Exists(PKGFileName + ".Dec"))
{
File.Delete(PKGFileName + ".Dec");
}
//Write File
FileStream DecryptedFileWriteStream = new FileStream(PKGFileName + ".Dec", FileMode.CreateNew, FileAccess.ReadWrite, FileShare.ReadWrite);
BinaryWriter bwDecryptedFile = new BinaryWriter(DecryptedFileWriteStream);
//Put the read pointer on the encrypted starting point.
PKGReadStream.Seek((int)uiEncryptedFileStartOffset, SeekOrigin.Begin);
// Pieces calculation
double filedivision = (double)uiEncryptedFileLenght / (double)(AesKey.Length * moltiplicator);
UInt64 filepieces = (UInt64)Math.Floor(filedivision);
UInt64 filemod = (UInt64)uiEncryptedFileLenght % (UInt64)(AesKey.Length * moltiplicator);
if (filemod > 0)
{
filepieces += 1;
}
progressBar.Value = 0;
progressBar.Maximum = (int)filepieces - 1;
progressBar.Step = 1;
Application.DoEvents();
for (UInt64 i = 0; i < filepieces; i++)
{
//If we have a mod and this is the last piece then...
if ((filemod > 0) && (i == (filepieces - 1)))
{
EncryptedData = new byte[filemod];
DecryptedData = new byte[filemod];
}
//Read 16 bytes of Encrypted data
EncryptedData = brPKG.ReadBytes(EncryptedData.Length);
//In order to retrieve a fast AES Encryption we pre-Increment the array
byte[] PKGFileKeyConsec = new byte[EncryptedData.Length];
byte[] PKGXorKeyConsec = new byte[EncryptedData.Length];
for (int pos = 0; pos < EncryptedData.Length; pos += AesKey.Length)
{
Array.Copy(incPKGFileKey, 0, PKGFileKeyConsec, pos, PKGFileKey.Length);
IncrementArray(ref incPKGFileKey, PKGFileKey.Length - 1);
}
//the incremented "file" key have to be encrypted with a "global AES key" to generate the "xor" key
//PSP uses CipherMode.ECB, PaddingMode.None that doesn't need IV
PKGXorKeyConsec = AESEngine.Encrypt(PKGFileKeyConsec, AesKey, AesKey, CipherMode.ECB, PaddingMode.None);
//XOR Decrypt and save every 16 bytes of data:
DecryptedData = XOREngine.XOR(EncryptedData, 0, PKGXorKeyConsec.Length, PKGXorKeyConsec);
progressBar.PerformStep();
Application.DoEvents();
bwDecryptedFile.Write(DecryptedData);
}
Application.DoEvents();
DecryptedFileWriteStream.Close();
bwDecryptedFile.Close();
return(PKGFileName + ".Dec");
}
catch (Exception ex)
{
txtResults.Text += "ERROR: An error occured during the decrypting process ";
SystemSounds.Beep.Play();
return(string.Empty);
}
}