private void ParseFile()
{
var directory = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
var path = $"{directory}\\Resources\\crypto\\encrypted_jpg_01.jpg";
string magic = "__CLOUDSYNC_ENC__";
byte[] magicBytes = Encoding.ASCII.GetBytes(magic);
using FileStream fs = new FileStream(path, FileMode.Open);
using BinaryReader br = new BinaryReader(fs);
byte[] value = br.ReadBytes(magicBytes.Length);
Console.WriteLine(ByteArrayCompare(magicBytes, value));
//check "__CLOUDSYNC_ENC__" Md5 hash
value = br.ReadBytes(32);
byte[] expectedMagicHash =
Encoding.ASCII.GetBytes(BytesUtils.ByteArrayToLowerHexString(Md5(magicBytes)));
Assert.AreEqual(expectedMagicHash, value);
//
HandlerFactory handlerFactory = new HandlerFactory();
StringHandler stringHandler = new StringHandler();
IntHandler intHandler = new IntHandler();
ByteSteamHandler byteSteamHandler = new ByteSteamHandler();
OrderedDictHandler dictHandler = new OrderedDictHandler(handlerFactory);
handlerFactory.AddHandler(stringHandler);
handlerFactory.AddHandler(dictHandler);
handlerFactory.AddHandler(intHandler);
handlerFactory.AddHandler(byteSteamHandler);
byte metaTag = br.ReadByte();
if (metaTag != 0x42)
{
throw new InvalidDataException();
}
IFileStreamHandler <IDictionary <string, object> > metaHandler =
handlerFactory.GetHandler <IDictionary <string, object> >(metaTag);
IDictionary <string, object> metaDict = metaHandler.Handle(br);
if (!(metaDict.ContainsKey("type") && "metadata".Equals(metaDict["type"])))
{
throw new InvalidDataException();
}
FileMeta3 fileMeta = FileMeta3.fromDictionary(metaDict);
Console.WriteLine(fileMeta);
AsymmetricKeyParameter akp = CryptoUtils.readPemPk(this.privateKey);
byte[] sessionKeyCharArray = CryptoUtils.RsaOaepDeciper(fileMeta.EncKey2, akp);
string computedSessionKeyHash = CryptoUtils.SaltedMd5(
fileMeta.SessionKeyHash.Substring(0, 10), sessionKeyCharArray);
if (!fileMeta.SessionKeyHash.Equals(computedSessionKeyHash))
{
throw new InvalidDataException("key is incorrect");
}
//decrypt content
byte[] sessionKey = BytesUtils.HexStringToByteArray(
Encoding.ASCII.GetString(sessionKeyCharArray));
Console.Write(sessionKey);
ParametersWithIV keys =
CryptoUtils.DeriveAESKeyParameters(sessionKey, null);
AesCbcCryptor decryptor =
new AesCbcCryptor(((KeyParameter)keys.Parameters).GetKey(), keys.GetIV());
List <byte[]> decryptedData = new List <byte[]>();
byte[] buf = null;
byte[] decBuf = null;
IDictionary <string, object> dataResult = null;
while (true)
{
byte dataTag = br.ReadByte();
if (dataTag == 0x40)
{
Console.WriteLine("come here");
}
if (dataTag != 0x42)
{
decBuf = decryptor.DecryptBlock(buf, true);
decryptedData.Add(decBuf);
break;
}
if (buf != null)
{
decBuf = decryptor.DecryptBlock(buf, false);
decryptedData.Add(decBuf);
}
IFileStreamHandler <IDictionary <string, object> > dataHandler =
handlerFactory.GetHandler <IDictionary <string, object> >(metaTag);
dataResult = dataHandler.Handle(br);
object typeValue = null;
dataResult.TryGetValue("type", out typeValue);
string typeValueString = typeValue as string;
if (!"data".Equals(typeValueString))
{
break;
}
buf = (byte[])dataResult["data"];
}
byte[] decData = CryptoUtils.Concat(decryptedData.ToArray());
File.WriteAllBytes("z:\\123.jpg.lz4", decData);
//last directory
//TODO validate dataResult["type"] == "metadata"
string fileMd5 = (string)dataResult["file_md5"];
Console.Write(fileMd5);
}
public bool ProcessFile(string sourcePath, string destDir, bool respectFileNameInMeta = true)
{
string destPath = null;
try
{
FileItem fi = new FileItem(sourcePath);
using (CloudSyncFile cloudSyncFile = new CloudSyncFile(fi, _handlerFactory))
{
cloudSyncFile.InitParsing();
FileMeta3 fileMeta = cloudSyncFile.GetFileMeta();
//Generate session key and make sure it matches the file
byte[] sessionKeyComputed =
CryptoUtils.RsaOaepDeciper(fileMeta.EncKey2, this._cloudSyncKey.KeyPair.Private);
string sessionKeyHashStrComputed = CryptoUtils.SaltedMd5(
fileMeta.SessionKeyHash.Substring(0, 10), sessionKeyComputed);
if (!fileMeta.SessionKeyHash.Equals(sessionKeyHashStrComputed))
{
throw new InvalidDataException($"File {fi.Name}, Computed session key is incorrect.");
}
//decrypt content
byte[] sessionKeyBytes = BytesUtils.HexStringToByteArray(
Encoding.ASCII.GetString(sessionKeyComputed));
ParametersWithIV keys =
CryptoUtils.DeriveAESKeyParameters(sessionKeyBytes, null);
AesCbcCryptor decryptor =
new AesCbcCryptor(((KeyParameter)keys.Parameters).GetKey(), keys.GetIV());
destPath = Path.Join(destDir,
respectFileNameInMeta ? fileMeta.FileName : Path.GetFileName(sourcePath));
using (var hasher = MD5.Create())
{
using (AesCryptoServiceProvider aes = new AesCryptoServiceProvider())
{
aes.Mode = CipherMode.CBC;
aes.Key = ((KeyParameter)keys.Parameters).GetKey();
aes.IV = keys.GetIV();
//Stopwatch stopwatch = new Stopwatch();
//stopwatch.Start();
//byte[] buffer = new byte[1024 * 1024];
long bytesRead = 0;
ICryptoTransform decoder = aes.CreateDecryptor();
using (CloudSyncPayloadStream cspls =
new CloudSyncPayloadStream(cloudSyncFile.GetDataBlocks(decryptor)))
using (CryptoStream aesStream = new CryptoStream(cspls, decoder, CryptoStreamMode.Read))
using (LZ4DecoderStream lz4ds = LZ4Stream.Decode(aesStream))
using (FileStream writeFs = new FileStream(destPath, FileMode.OpenOrCreate,
FileAccess.ReadWrite, FileShare.ReadWrite, 1024 * 1024))
using (CryptoStream md5HashStream =
new CryptoStream(writeFs, hasher, CryptoStreamMode.Write))
{
lz4ds.CopyTo(md5HashStream, 1024 * 1024);
// int read;
// while ((read = md5HashStream.Read(buffer, 0, buffer.Length)) > 0)
// {
// //do nothing
// bytesRead += read;
// long elapsed = stopwatch.ElapsedMilliseconds;
// if (elapsed > 1000)
// {
// double readInM = (double) bytesRead / 1024.0 / 1024.0/elapsed*1000.0;
// bytesRead = 0;
// Console.WriteLine($"Speed:{readInM} M/s");
// stopwatch.Reset();
// stopwatch.Start();
// }
// }
}
//stopwatch.Stop();
if (!cloudSyncFile.VerifyContentHash(hasher.Hash))
{
throw new InvalidDataException("File Md5 doesn't match.");
}
}
}
return(true);
}
}
catch (Exception ex)
{
if (File.Exists(destPath))
{
File.Delete(destPath);
}
this._exceptionHandler.Handle(ex);
}
return(false);
}
