| public static SymmetricDecrypt ( byte input, byte key ) : byte[] | ||
| input | byte | |
| key | byte | |
| return | byte[] | |
/// <summary>
/// Verifies and performs a symmetricdecrypt on the input using the given password as a key
/// </summary>
public static byte[] VerifyAndDecryptPassword(byte[] input, string password)
{
byte[] key, hash;
using (SHA256 sha256 = SHA256Managed.Create())
{
byte[] password_bytes = Encoding.ASCII.GetBytes(password);
key = sha256.ComputeHash(password_bytes);
}
using (HMACSHA1 hmac = new HMACSHA1(key))
{
hash = hmac.ComputeHash(input, 0, 32);
}
for (int i = 32; i < input.Length; i++)
{
if (input[i] != hash[i % 32])
{
return(null);
}
}
byte[] encrypted = new byte[32];
Array.Copy(input, 0, encrypted, 0, 32);
return(CryptoHelper.SymmetricDecrypt(encrypted, key));
}
/// <summary>
/// Processes the specified depot key by decrypting the data with the given depot encryption key, and then by decompressing the data.
/// If the chunk has already been processed, this function does nothing.
/// </summary>
/// <param name="depotKey">The depot decryption key.</param>
/// <exception cref="System.IO.InvalidDataException">Thrown if the processed data does not match the expected checksum given in it's chunk information.</exception>
public void Process(byte[] depotKey)
{
if (depotKey == null)
{
throw new ArgumentNullException(nameof(depotKey));
}
if (IsProcessed)
{
return;
}
byte[] processedData = CryptoHelper.SymmetricDecrypt(Data, depotKey);
if (processedData.Length > 1 && processedData[0] == 'V' && processedData[1] == 'Z')
{
processedData = VZipUtil.Decompress(processedData);
}
else
{
processedData = ZipUtil.Decompress(processedData);
}
byte[] dataCrc = CryptoHelper.AdlerHash(processedData);
if (!dataCrc.SequenceEqual(ChunkInfo.Checksum))
{
throw new InvalidDataException("Processed data checksum is incorrect! Downloaded depot chunk is corrupt or invalid/wrong depot key?");
}
Data = processedData;
IsProcessed = true;
}
/// <summary>
/// Attempts to decrypts file names with the given encryption key.
/// </summary>
/// <param name="encryptionKey">The encryption key.</param>
/// <returns><c>true</c> if the file names were successfully decrypted; otherwise, <c>false</c>.</returns>
public bool DecryptFilenames(byte[] encryptionKey)
{
if (!FilenamesEncrypted)
{
return(true);
}
foreach (var file in Files)
{
byte[] enc_filename = Convert.FromBase64String(file.FileName);
byte[] filename;
try
{
filename = CryptoHelper.SymmetricDecrypt(enc_filename, encryptionKey);
}
catch (Exception)
{
return(false);
}
file.FileName = Encoding.ASCII.GetString(filename).TrimEnd(new char[] { '\0' }).Replace(altDirChar, Path.DirectorySeparatorChar);
}
FilenamesEncrypted = false;
return(true);
}
/// <summary>
/// Attempts to decrypts file names with the given encryption key.
/// </summary>
/// <param name="encryptionKey">The encryption key.</param>
/// <returns><c>true</c> if the file names were successfully decrypted; otherwise, <c>false</c>.</returns>
public bool DecryptFilenames(byte[] encryptionKey)
{
if (!FilenamesEncrypted)
{
return(true);
}
DebugLog.Assert(Files != null, nameof(DepotManifest), "Files was null when attempting to decrypt filenames.");
foreach (var file in Files)
{
byte[] enc_filename = Convert.FromBase64String(file.FileName);
byte[] filename;
try
{
filename = CryptoHelper.SymmetricDecrypt(enc_filename, encryptionKey);
}
catch (Exception)
{
return(false);
}
file.FileName = Encoding.UTF8.GetString(filename).TrimEnd(new char[] { '\0' }).Replace(altDirChar, Path.DirectorySeparatorChar);
}
FilenamesEncrypted = false;
return(true);
}
/// <summary>
/// Processes a chunk by decrypting and decompressing it.
/// </summary>
/// <param name="chunk">The chunk to process.</param>
/// <param name="depotkey">The AES encryption key to use when decrypting the chunk.</param>
/// <returns>The processed chunk.</returns>
public static byte[] ProcessChunk(byte[] chunk, byte[] depotkey)
{
byte[] decrypted_chunk = CryptoHelper.SymmetricDecrypt(chunk, depotkey);
byte[] decompressed_chunk = ZipUtil.Decompress(decrypted_chunk);
return(decompressed_chunk);
}
public byte[] ProcessIncoming(byte[] data)
{
try
{
return(CryptoHelper.SymmetricDecrypt(data, sessionKey));
}
catch (CryptographicException ex)
{
DebugLog.WriteLine("NetFilterEncryption", "Unable to decrypt incoming packet: " + ex.Message);
// rethrow as an IO exception so it's handled in the network thread
throw new IOException("Unable to decrypt incoming packet", ex);
}
}
/// <summary>
/// Processes the specified depot key by decrypting the data with the given depot encryption key, and then by decompressing the data.
/// If the chunk has already been processed, this function does nothing.
/// </summary>
/// <param name="depotKey">The depot decryption key.</param>
/// <exception cref="System.IO.InvalidDataException">Thrown if the processed data does not match the expected checksum given in it's chunk information.</exception>
public void Process(byte[] depotKey)
{
if (IsProcessed)
{
return;
}
byte[] processedData = CryptoHelper.SymmetricDecrypt(Data, depotKey);
processedData = ZipUtil.Decompress(processedData);
byte[] dataCrc = CryptoHelper.AdlerHash(processedData);
if (!dataCrc.SequenceEqual(ChunkInfo.Checksum))
{
throw new InvalidDataException("Processed data checksum is incorrect! Downloaded depot chunk is corrupt or invalid/wrong depot key?");
}
Data = processedData;
IsProcessed = true;
}
/// <summary>
/// Verifies and performs a symmetricdecrypt on the input using the given password as a key
/// </summary>
public static byte[]? VerifyAndDecryptPassword(byte[] input, string password)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (password == null)
{
throw new ArgumentNullException(nameof(password));
}
byte[] key, hash;
using (var sha256 = SHA256.Create())
{
byte[] password_bytes = Encoding.UTF8.GetBytes(password);
key = sha256.ComputeHash(password_bytes);
}
using (HMACSHA1 hmac = new HMACSHA1(key))
{
hash = hmac.ComputeHash(input, 0, 32);
}
for (int i = 32; i < input.Length; i++)
{
if (input[i] != hash[i % 32])
{
return(null);
}
}
byte[] encrypted = new byte[32];
Array.Copy(input, encrypted, encrypted.Length);
return(CryptoHelper.SymmetricDecrypt(encrypted, key));
}
/// <summary>
/// Processes the specified depot key by decrypting the data with the given depot encryption key, and then by decompressing the data.
/// If the chunk has already been processed, this function does nothing.
/// </summary>
/// <param name="depotKey">The depot decryption key.</param>
/// <exception cref="System.IO.InvalidDataException">Thrown if the processed data does not match the expected checksum given in it's chunk information.</exception>
public void Process(byte[] depotKey)
{
if (depotKey == null)
{
throw new ArgumentNullException(nameof(depotKey));
}
if (IsProcessed)
{
return;
}
if (Data != null)
{
byte[] processedData = CryptoHelper.SymmetricDecrypt(Data, depotKey);
if (processedData.Length > 1 && processedData[0] == 'V' && processedData[1] == 'Z')
{
processedData = VZipUtil.Decompress(processedData);
}
else
{
processedData = ZipUtil.Decompress(processedData);
}
byte[] dataCrc = CryptoHelper.AdlerHash(processedData);
if (!dataCrc.SequenceEqual(ChunkInfo.Checksum))
{
throw new InvalidDataException("Processed data checksum is incorrect! Downloaded depot chunk is corrupt or invalid/wrong depot key?");
}
Data = processedData;
IsProcessed = true;
}
if (DataStream != null)
{
Stream reProcessedData;
using (Stream processedData = CryptoHelper.SymmetricDecrypt(DataStream, depotKey))
{
int firstByte = processedData.ReadByte();
int secondByte = processedData.ReadByte();
processedData.Position = 0;
if (firstByte == 86 && secondByte == 90)
{
reProcessedData = VZipUtil.Decompress(processedData);
}
else
{
reProcessedData = ZipUtil.Decompress(processedData);
}
}
byte[] dataCrc = CryptoHelper.AdlerHash(reProcessedData);
if (!dataCrc.SequenceEqual(ChunkInfo.Checksum))
{
throw new InvalidDataException("Processed data checksum is incorrect! Downloaded depot chunk is corrupt or invalid/wrong depot key?");
}
DataStream = reProcessedData;
IsProcessed = true;
}
}
public byte[] ProcessIncoming(byte[] data)
{
return(CryptoHelper.SymmetricDecrypt(data, sessionKey));
}