public static StorageMetadata CreateStorageFile(Stream dataStream, uint archiveNumber, ulong?profileKey)
{
StorageMetadata metadata = new StorageMetadata();
metadata.ArchiveNumber = archiveNumber + 2;
byte[] data = null;
using (BinaryReader reader = new BinaryReader(dataStream))
{
data = reader.ReadBytes((int)reader.BaseStream.Length);
}
Array.Resize(ref data, data.Length + 1); // 1 byte null padding
// Generate Spooky hash of data for later
SpookyHash sh = new SpookyHash(0x155af93ac304200, 0x8ac7230489e7ffff);
sh.Update(new SHA256Managed().ComputeHash(data));
sh.Update(data);
sh.Final(out metadata.Key[0], out metadata.Key[1]);
var compressedData = Compress(data);
var key = GenerateKey(metadata, profileKey, true);
metadata.StorageRaw = XXTEA.Encrypt(compressedData, key);
metadata.CompressedSize = (uint)compressedData.Length;
metadata.DecompressedSize = (uint)data.Length;
return(metadata);
}
private static void ParseStorageFile(StorageMetadata metadata, Stream storageStream, ulong?profileKey = null)
{
byte[] data = null;
using (BinaryReader reader = new BinaryReader(storageStream))
{
data = reader.ReadBytes((int)reader.BaseStream.Length);
}
var rawSha256 = new SHA256Managed().ComputeHash(data);
var sha256 = BitConverter.ToString(rawSha256).Replace("-", "");
if (sha256 != metadata.SHA256)
{
throw new InvalidDataException("Invalid storage file. Corrupt or wrong file?");
}
if (metadata.StorageVersion == STORAGE_VERSION_V1)
{
var key = GenerateKey(metadata, profileKey);
var decryptedData = XXTEA.Decrypt(data, key);
var output = Decompress(metadata, decryptedData);
// Verify data
SpookyHash sh = new SpookyHash(0x155af93ac304200, 0x8ac7230489e7ffff);
sh.Update(new SHA256Managed().ComputeHash(output));
sh.Update(output);
ulong hash1, hash2;
sh.Final(out hash1, out hash2);
ulong orig_hash1 = metadata.Key[0];
ulong orig_hash2 = metadata.Key[1];
if (orig_hash1 != hash1 || orig_hash2 != hash2)
{
throw new InvalidDataException("Invalid decrypted data. Wrong key?");
}
metadata.StorageRaw = output;
}
else
{
SpookyHash sh = new SpookyHash(0x155af93ac304200, 0x8ac7230489e7ffff);
sh.Update(rawSha256);
sh.Update(data);
ulong hash1, hash2;
sh.Final(out hash1, out hash2);
ulong orig_hash1 = metadata.Key[0];
ulong orig_hash2 = metadata.Key[1];
if (orig_hash1 != hash1 || orig_hash2 != hash2)
{
throw new InvalidDataException("Invalid decrypted data. Wrong key?");
}
metadata.StorageRaw = data;
}
}
private static byte[] GenerateKey(StorageMetadata metadata, ulong?profileKey, bool storeProfileKey = false)
{
uint[] keydata_ints = { 0, 0, 0, 0 };
uint k1_h = (uint)metadata.Key[0] & 0xffff;
uint k1_d = (uint)(metadata.Key[0] >> 5) & 0x7fff800;
uint k2_h = (uint)(metadata.Key[0] >> 32) & 0xffff;
uint k2_d = (uint)((metadata.Key[0] >> 32) >> 5) & 0x7fff800;
uint k3_h = (uint)metadata.Key[1] & 0xffff;
uint k3_d = (uint)(metadata.Key[1] >> 5) & 0x7fff800;
uint k4_h = (uint)(metadata.Key[1] >> 32) & 0xffff;
uint k4_d = (uint)((metadata.Key[1] >> 32) >> 5) & 0x7fff800;
// More murmurhash-like code
uint temp = 0;
// Byte 1
temp = F1(0x85EBCA6B, k1_h, k1_d, k2_h, k2_d);
temp = F2(((temp >> 6) + temp), metadata.ArchiveNumber);
keydata_ints[0] = temp;
// Byte 2
temp = F1(0xCC9E2D51, k3_h, k3_d, k4_h, k4_d);
temp += (temp >> 6);
keydata_ints[1] = temp;
// Byte 3
temp = F1(0x1b873593, k1_h, k1_d, k2_h, k2_d);
temp += (temp >> 6);
keydata_ints[2] = temp;
// Byte 4
temp = F1(0x85EBCA6B, k3_h, k3_d, k4_h, k4_d);
temp += (temp >> 6);
keydata_ints[3] = temp;
if (metadata.ProfileHash.HasValue || (profileKey.HasValue && storeProfileKey))
{
if (profileKey.HasValue)
{
// Decrypt using Steam/GOG ID key
uint profile_key_h = (uint)(profileKey.Value & 0xffff);
uint profile_key_d = (uint)((profileKey.Value >> 5) & 0x7fff800);
uint profile_key_h2 = (uint)((profileKey.Value >> 0x20) & 0xffff);
uint profile_key_d2 = (uint)(((profileKey.Value >> 0x20) >> 5) & 0x7fff800);
temp = F1(0x1b873593, profile_key_h, profile_key_d, profile_key_h2, profile_key_d2);
temp += (temp >> 6);
uint hashCheck = temp & 0xffff;
if (storeProfileKey)
{
metadata.ProfileHash = hashCheck;
}
keydata_ints[1] = F2(keydata_ints[1], temp);
if (hashCheck != metadata.ProfileHash)
{
throw new InvalidDataException("Invalid data: profile hash did not check out");
}
}
else
{
throw new ArgumentException("Must provide profile key to decrypt this data");
}
}
return(keydata_ints.SelectMany(BitConverter.GetBytes).ToArray());
}
// Creation code
public static void CreateMetadataFile(StorageMetadata metadata)
{
var sha256 = new SHA256Managed().ComputeHash(metadata.StorageRaw);
// Murmurhash-like
uint k1 = metadata.ArchiveNumber ^ 0x1422cb8c;
uint h1 = RotateLeft(k1, 13) * 5 + 0xe6546b64;
var input_key = Encoding.ASCII.GetBytes("NAESEVADNAYRTNRG");
for (int i = 0; i < 4; i++)
{
input_key[i] = (byte)(h1 >> (i * 8));
}
List <uint> key = new List <uint>();
for (int i = 0; i < input_key.Length; i += 4)
{
key.Add(BitConverter.ToUInt32(input_key, i));
}
var metadataBuffer = new byte[0x68];
using (BinaryWriter writer = new BinaryWriter(new MemoryStream(metadataBuffer)))
{
writer.Write(0xeeeeeebe);
writer.Write(0x7d0);
writer.Write(metadata.Key[0]);
writer.Write(metadata.Key[1]);
writer.Write(sha256);
writer.Write(metadata.DecompressedSize);
writer.Write(metadata.CompressedSize);
if (metadata.ProfileHash.HasValue)
{
writer.Write(metadata.ProfileHash.Value);
}
}
List <uint> data = new List <uint>();
using (BinaryReader reader = new BinaryReader(new MemoryStream(metadataBuffer)))
{
while (reader.BaseStream.Position < reader.BaseStream.Length)
{
data.Add(reader.ReadUInt32());
}
}
uint hash = 0;
uint cur = 0;
for (int itr1 = 0; itr1 < 8; itr1++)
{
hash += 0x9E3779B9;
int key_idx = (int)((hash >> 2) & 3);
int idx = 0;
uint tmp = 0;
for (int itr2 = 0; itr2 < 0x19; itr2++, idx++)
{
tmp = ((data[idx + 1] >> 3) ^ (cur << 4)) + ((data[idx + 1] * 4) ^ (cur >> 5));
tmp ^= (cur ^ key[(itr2 & 3) ^ key_idx]) + (data[idx + 1] ^ hash);
data[idx] += tmp;
cur = data[idx];
}
tmp = ((data[0] >> 3) ^ (cur << 4)) + ((data[0] * 4) ^ (cur >> 5));
tmp ^= (cur ^ key[key_idx ^ 1]) + (data[0] ^ hash);
data[data.Count - 1] += tmp;
cur = data[data.Count - 1];
}
metadata.MetadataRaw = data.SelectMany(BitConverter.GetBytes).ToArray();
}
private static byte[] Decompress(StorageMetadata metadata, byte[] data)
{
List <byte> output = new List <byte>();
int i = 0;
int window = 0;
while (i < metadata.CompressedSize)
{
var c = data[i++];
for (int x = 1; x >= 0; x--)
{
int size = ((c >> (0x04 * x)) & 0xf);
if (output.Count >= metadata.DecompressedSize)
{
break;
}
if (size == 0x0f)
{
do
{
size += data[i++];
} while (data[i - 1] == 0x0ff);
}
if (x == 1)
{
byte[] temp_data = new byte[size];
Array.Copy(data, i, temp_data, 0, size);
output.AddRange(temp_data);
i += size;
if (output.Count >= metadata.DecompressedSize)
{
break;
}
window = output.Count - BitConverter.ToUInt16(data, i);
i += 2;
}
else
{
size += 4;
byte[] temp_data = new byte[size];
int copySize = size > (output.Count - window) ? (output.Count - window) : size;
for (int idx = 0; idx < copySize; idx++)
{
temp_data[idx] = output[window + idx];
}
int remaining = size - copySize;
int offset = copySize;
while (remaining > 0)
{
copySize = remaining > offset ? offset : remaining;
Array.Copy(temp_data, 0, temp_data, offset, copySize);
remaining -= copySize;
offset += copySize;
}
output.AddRange(temp_data);
}
}
}
return(output.ToArray());
}
// Loading code
private static StorageMetadata ParseMetadataFile(Stream input, uint archiveNumber)
{
archiveNumber += 2;
List <uint> data = new List <uint>();
using (BinaryReader reader = new BinaryReader(input))
{
while (reader.BaseStream.Position < reader.BaseStream.Length)
{
data.Add(reader.ReadUInt32());
}
}
if (data.Count * 4 != 0x68)
{
throw new InvalidDataException("Invalid metadata file. Expected a file of size 0x68");
}
// Murmurhash-like
uint k1 = archiveNumber ^ 0x1422cb8c;
uint h1 = RotateLeft(k1, 13) * 5 + 0xe6546b64;
var input_key = Encoding.ASCII.GetBytes("NAESEVADNAYRTNRG");
for (int i = 0; i < 4; i++)
{
input_key[i] = (byte)(h1 >> (i * 8));
}
List <uint> key = new List <uint>();
for (int i = 0; i < input_key.Length; i += 4)
{
key.Add(BitConverter.ToUInt32(input_key, i));
}
uint hash = 0xf1bbcdc8;
for (int itr1 = 0; itr1 < 8; itr1++)
{
int key_idx = (int)((hash >> 2) & 3);
uint cur = data[0];
int idx = data.Count - 1;
uint tmp = 0;
for (int itr2 = 0x19; itr2 > 0; itr2--, idx--)
{
tmp = ((cur >> 3) ^ (data[idx - 1] << 4)) + ((cur * 4) ^ (data[idx - 1] >> 5));
tmp ^= (data[idx - 1] ^ key[(itr2 & 3) ^ key_idx]) + (cur ^ hash);
data[idx] -= tmp;
cur = data[idx];
}
idx = data.Count - 1;
tmp = (((cur >> 3) ^ (data[idx] << 4)) + ((cur * 4) ^ (data[idx] >> 5))) & 0xffffffff;
tmp ^= (((data[idx] ^ key[key_idx]) + (cur ^ hash)) & 0xffffffff);
data[0] -= tmp;
hash += 0x61c88647;
}
// Check fixed header values to make sure decryption worked
if (data[0] != 0xeeeeeebe || data[1] != 0x7d0)
{
throw new InvalidDataException("Invalid metadata archive");
}
// Get SHA-256 hash from data
var sha256 = BitConverter.ToString(data.Skip(6).Take(8).SelectMany(BitConverter.GetBytes).ToArray()).Replace("-", "");
// Get encryption key for data
var dataKey = data.Skip(2).Take(4).ToArray();
StorageMetadata metadata = new StorageMetadata();
metadata.Key = new ulong[] { ((ulong)dataKey[1] << 32) | dataKey[0], ((ulong)dataKey[3] << 32) | dataKey[2] };
metadata.SHA256 = sha256;
metadata.DecompressedSize = data[14];
metadata.CompressedSize = data[15];
metadata.ArchiveNumber = archiveNumber;
if (data[16] != 0)
{
metadata.ProfileHash = data[16];
}
return(metadata);
}