c# RijndaelManaged encryption & decryption sometimes fails - c#

Edit: solved - problem was the decryption function. Corrected decryption function can be found in the answer below.
I have spent the last day at work trying to figure out where I went wrong with this implementation of AES. We need to be able to encrypt/decrypt large files so I have used file streams and write to disk each chunk. AES is a requirement as this needs to work with an existing system written in java which uses AES/CBC/PKCS5Padding (which as far as I am aware is equivalent to PKCS7/CBC)
This implementation works for most files. However there are a few files where the last 5 bytes of raw data are missing. The file will decrypt without errors however the hash doesn't match and the missing bytes are a combination of real data and trailing zeros.
It should be noted that these streams are gzipped before and after encryption (code at the bottom).
Encryption
public static void AesEncrypt(byte[] keyBytes, byte[] ivBytes, Stream dataStream, FileStream outStream)
{
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
symmetricKey.BlockSize = 128;
symmetricKey.KeySize = 256;
const int chunkSize = 4096;//1024 * 1024 * 10;
using (ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, ivBytes))
{
using (CryptoStream cryptoStream = new CryptoStream(outStream, encryptor, CryptoStreamMode.Write))
{
while (dataStream.Position != dataStream.Length)
{
long remainingBytes = dataStream.Length - dataStream.Position;
var buffer = chunkSize > remainingBytes ? new byte[(int)remainingBytes] : new byte[chunkSize];
dataStream.Read(buffer, 0, buffer.Length);
cryptoStream.Write(buffer, 0, buffer.Length);
cryptoStream.Flush();
}
cryptoStream.FlushFinalBlock();
}
}
symmetricKey.Clear();
}
Decryption
public static void AesDecrypt(byte[] keyBytes, byte[] ivBytes, Stream dataStream, FileStream outStream)
{
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
symmetricKey.BlockSize = 128;
symmetricKey.KeySize = keyBytes.Length == 32 ? 256 : 128;
const int chunkSize = 4096;
using (ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, ivBytes))
{
using (CryptoStream cryptoStream = new CryptoStream(dataStream, decryptor, CryptoStreamMode.Read))
{
while (dataStream.Position != dataStream.Length)
{
long remainingBytes = dataStream.Length - dataStream.Position;
var buffer = chunkSize > remainingBytes
? new byte[(int) remainingBytes]
: new byte[chunkSize];
cryptoStream.Read(buffer, 0, buffer.Length);
outStream.Write(buffer, 0, buffer.Length);
outStream.Flush();
}
//cryptoStream.FlushFinalBlock(); // Was throwing an exception
}
}
symmetricKey.Clear();
}
Compression (Prior to encryption)
public static void StreamCompress(Stream dataStream, FileStream outStream)
{
dataStream.Position = 0;
outStream.Position = 0;
const int chunkSize = 4096;
using (GZipStream gzs = new GZipStream(outStream, CompressionMode.Compress))
{
while (dataStream.Position != dataStream.Length)
{
long remainingBytes = dataStream.Length - dataStream.Position;
var buffer = chunkSize > remainingBytes ? new byte[(int)remainingBytes] : new byte[chunkSize];
dataStream.Read(buffer, 0, buffer.Length);
gzs.Write(buffer, 0, buffer.Length);
gzs.Flush();
}
}
}
Decompression (After decryption)
public static void StreamDecompress(Stream dataStream, FileStream outStream)
{
byte[] buffer = new byte[4096];
dataStream.Position = 0;
using (GZipStream gzs = new GZipStream(dataStream, CompressionMode.Decompress))
{
for (int r = -1; r != 0; r = gzs.Read(buffer, 0, buffer.Length))
if (r > 0) outStream.Write(buffer, 0, r);
}
}
I have gone through some other questions but cannot figure out why this only occurs on some files. The file size which fails is 46,854,144 bytes. This seems to work fine with larger and smaller files though.
Any help would be greatly appreciated.

The issue was with the way I was decrypting the data. I was incorrectly using the CryptoStream. The updated Decrypt function is below if anyone was interested.
public static void AesDecrypt(byte[] keyBytes, byte[] ivBytes, Stream dataStream, FileStream outStream)
{
dataStream.Position = 0;
outStream.Position = 0;
RijndaelManaged symmetricKey = new RijndaelManaged();
symmetricKey.Mode = CipherMode.CBC;
symmetricKey.Padding = PaddingMode.PKCS7;
symmetricKey.BlockSize = 128;
symmetricKey.KeySize = keyBytes.Length == 32 ? 256 : 128;
const int chunkSize = 4096;
using (ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, ivBytes))
{
using (CryptoStream cryptoStream = new CryptoStream(outStream, decryptor, CryptoStreamMode.Write))
{
while (dataStream.Position != dataStream.Length)
{
long remainingBytes = dataStream.Length - dataStream.Position;
var buffer = chunkSize > remainingBytes
? new byte[(int) remainingBytes]
: new byte[chunkSize];
var bytesRead = dataStream.Read(buffer, 0, buffer.Length);
cryptoStream.Write(buffer, 0, bytesRead);
}
cryptoStream.FlushFinalBlock();
}
}
symmetricKey.Clear();
}

Related

Issues with Decrypt data with length and padding

I have issues to get the data decrypted and not sure what I do wrong as tried almost everything.
private static byte[] AES_Encrypt(byte[] byteArray)
{
byte[] salt = GenerateRandomSalt();
MemoryStream fsCrypt = new MemoryStream();
byte[] ms = new byte[0];
byte[] passwordBytes = System.Text.Encoding.UTF8.GetBytes(keyName);
RijndaelManaged AES = new RijndaelManaged();
AES.KeySize = 256;
AES.BlockSize = 128;
AES.Padding = PaddingMode.None;
var key = new Rfc2898DeriveBytes(passwordBytes, salt, 50000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CFB;
fsCrypt.Write(salt, 0, salt.Length);
CryptoStream cs = new CryptoStream(fsCrypt, AES.CreateEncryptor(), CryptoStreamMode.Write);
MemoryStream fsIn = new MemoryStream(byteArray);
byte[] buffer = new byte[1048576];
int read;
try
{
if (byteArray.Length <= buffer.Length)
cs.Write(buffer, 0, buffer.Length);
else
while ((read = fsIn.Read(buffer, 0, buffer.Length)) > 0)
{
cs.Write(buffer, 0, read);
}
ms = fsCrypt.ToArray();
fsIn.Close();
}
catch (Exception ex)
{
}
finally
{
try
{
cs.Close();
fsCrypt.Close();
}
catch (Exception err)
{
}
}
string response = Encoding.UTF8.GetString(ms.ToArray());
return ms.ToArray();
}
private static byte[] AES_Decrypt(byte[] byteArray)
{
byte[] passwordBytes = System.Text.Encoding.UTF8.GetBytes(keyName);
byte[] salt = new byte[32];
byte[] ms = new byte[0];
MemoryStream fsCrypt = new MemoryStream(byteArray);
fsCrypt.Read(salt, 0, salt.Length);
RijndaelManaged AES = new RijndaelManaged();
AES.KeySize = 256;
AES.BlockSize = 128;
var key = new Rfc2898DeriveBytes(passwordBytes, salt, 50000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Padding = PaddingMode.None;
AES.Mode = CipherMode.CFB;
MemoryStream fsOut = new MemoryStream();
CryptoStream cs = new CryptoStream(fsCrypt, AES.CreateDecryptor(), CryptoStreamMode.Read);
int read;
byte[] buffer = new byte[1048576];
try
{
string response = Encoding.UTF8.GetString(byteArray);
if (byteArray.Length <= buffer.Length)
{
while ((read = cs.Read(byteArray, 0, byteArray.Length)) > 0)
{
fsOut.Read(byteArray, 0, read);
}
string vresponse = Encoding.UTF8.GetString(fsOut.ToArray());
}
else
while ((read = cs.Read(buffer, 0, buffer.Length)) > 0)
{
fsOut.Write(buffer, 0, read);
}
}
catch (System.Security.Cryptography.CryptographicException ex_CryptographicException)
{
}
catch (Exception ex)
{
}
try
{
cs.Close();
}
catch (Exception ex)
{
}
finally
{
fsOut.Close();
//fsCrypt.Close();
}
return ms.ToArray();
}
My data is sometimes shorter than the 1MB being used so I want to catch th shorter data to use less byte, however its for later concern.
The data I send to the decryptor is using the same static keys now and the inbound encrypted data is identical as the out type encrypted data.
If I put the PaddingMode.None; to PaddingMode.PKCS7 it gives me a mapping error, which comes as I assume in the shorter string than the buffer actually is, so as far my assumations this is correct, so I use for now 'none'.
I have looked to lots of links as:
https://stackoverflow.com/questions/31486028/decrypting-cryptostream-into-memorystream
https://stackoverflow.com/questions/31486028/decrypting-cryptostream-into-memorystream
https://stackoverflow.com/questions/8583112/padding-is-invalid-and-cannot-be-removed
[Encrypt to memory stream, pass it to file stream
[AES encryption on large files
The problem I cant figure out why the encrypted data wont decrypt as should.
100% sure I do something not correct but cant figure out what, any help would be appriciated.
I have changes some code and tried different options, now using this but on both option I get errors.
using (var msi = new MemoryStream())
{
try
{
using (var cs = new CryptoStream(msi, aesAlg.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(bytes, 0, bytes.Length); //Option 1, gives error, length is invalid of byte array
do //Option 2, give error, Padding is invalid and cannot be removed.
{
count = msi.Read(bytes, 0, blockSizeBytes);
offset += count;
cs.Write(data, 0, count);
}
while (count > 0);
}
var plainText = msi.ToArray();
var text = Encoding.Unicode.GetString(plainText);
}
catch (Exception e)
{
}
//return text;
}
I checked the data length and using Unicode encoding it is 4258 and the bytes are 8516, which should be from my point of view as using Unicode.
Not sure if using the right encoding as found this https://stackoverflow.com/a/10380166/3763117 and can do without but gives same lengthas unicode. little stucked on this any help with some samples would be appriciated.

C# Send byte[] to server, decrypt content and send it as byte[] back to client

My problem is the following:
I have a client/server application connected over sockets. My client´s task is to send a file byte-wise to the server. The server gets the bytes, decrypt them, send it back to the client and he writes them in a new file on disk.
I get everytime a serverside exception (System.Security.Cryptography.Exception: Padding is invalid and cannot be removed) at this line of code: plaintext = sr.ReadToEnd();
Could somebody help me to solve my problem?
Here is the decryption code:
public byte[] Dec(byte[] content, byte[] Key, byte[] IV, int fileLength, string filepath, int chunkSize, int bytesToRead)
{
byte[] contentDec;
string plaintext = null;
System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("IV");
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
using (MemoryStream ms = new MemoryStream(content))
{
using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
{
using (StreamReader sr = new StreamReader(cs))
{
plaintext = sr.ReadToEnd();
cs.FlushFinalBlock();
}
contentDec = encoding.GetBytes(plaintext);
}
}
}
return contentDec;
}
Here is my encryption code:
public byte[] Enc(byte[] content,byte[] Key, byte[] IV, int fileLength,string filepath, int chunkSize, int bytesToRead)
{
byte[] contentEnc;
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
if (IV == null || IV.Length <= 0)
throw new ArgumentNullException("IV");
using (RijndaelManaged rijAlg = new RijndaelManaged())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter sw = new StreamWriter(cs))
{
sw.Write(content);
}
contentEnc = ms.ToArray();
}
}
}
return contentEnc;
}
On client side I call encryption method like this
int chunkSize = 1024;
byte[] chunk = new byte[chunkSize];
using (FileStream fileReader = new FileStream(plainPath, FileMode.Open, FileAccess.Read))
using (FileStream filewriter = new FileStream(pathEncrypt, FileMode.Create, FileAccess.ReadWrite))
using (BinaryReader binaryReader = new BinaryReader(fileReader))
using (RijndaelManaged myRijndael = new RijndaelManaged())
{
myRijndael.GenerateKey();
myRijndael.GenerateIV();
Key = myRijndael.Key;
IV = myRijndael.IV;
int bytesToRead = (int)fileReader.Length;
do
{
chunk = service.Enc(binaryReader.ReadBytes(chunkSize), Key, IV,(int)fileReader.Length,
fileReader.Name, chunkSize, bytesToRead);
filewriter.Write(chunk, 0, chunk.Length);
bytesToRead -= chunkSize;
} while (bytesToRead > 0);
}
Key and IV are declared as private byte[]
On client side I call decryption method like this
int chunkSize = 1024;
byte[] chunk = new byte[chunkSize];
using (FileStream fileReader = new FileStream(pathEncrypt, FileMode.Open, FileAccess.Read))
using (FileStream filewriter = new FileStream(pathDecrypt, FileMode.Create, FileAccess.ReadWrite))
using (BinaryReader binaryReader = new BinaryReader(fileReader))
{
int bytesToRead = (int)fileReader.Length;
do
{
chunk = service.Dec(binaryReader.ReadBytes(chunkSize), Key, IV, (int)fileReader.Length,
fileReader.Name, chunkSize, bytesToRead);
filewriter.Write(chunk, 0, chunk.Length);
bytesToRead -= chunkSize;
} while (bytesToRead > 0);
}
Edit: This is my connection establishment between client and server.
Server:
var host = new ServiceHost(typeof(Service),
new Uri("net.pipe://localhost"));
host.AddServiceEndpoint(typeof(TiService),
new NetNamedPipeBinding(), "TestService");
host.Open();
Console.WriteLine("Server connection established...");
Console.ReadKey();
Client:
var callback = new Callback();
var context = new InstanceContext(callback);
var pipeFactory =
new DuplexChannelFactory<TiService>(context,
new NetNamedPipeBinding(),
new EndpointAddress("net.pipe://localhost/TestService"));
service = pipeFactory.CreateChannel();
service.Connect();
Your problem start from using StreamWriter in the encryption. It's meant for writing Text file, not arbitrary file. When you call sw.Write(content), it simply call content.ToString(), which return "System.Byte[]", instead what you'd probably expect, each byte of the array. To fix it, simply write the CryptoStream, no need to use StreamWriter, like this :
using (var rijAlg = new AesCng())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
ICryptoTransform encryptor = rijAlg.CreateEncryptor();
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
cs.Write(content, 0, content.Length);
}
contentEnc = ms.ToArray();
}
}
You probably noticed I used AesCng instead of RijndaelManaged. Why? Because it's much faster in my test, and unless you really need non-standard block, there's no benefit of using RijndaelManaged. Also, I use the parameterless CreateEncryptor because you already set the Key & IV on the previous lines anyway.
Same deal in the decryption. You shouldn't treat them as text, thus :
var buffer = new byte[content.Length]; //at first its size is actual size+padding
using (var rijAlg = new AesCng())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
ICryptoTransform decryptor = rijAlg.CreateDecryptor();
using (MemoryStream ms = new MemoryStream(content))
{
using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
{
var actualSize = cs.Read(buffer, 0, content.Length);
//we write the decrypted content to the buffer, and get the actual size
Array.Resize(ref buffer, actualSize);
//then we resize the buffer to the actual size
}
}
}
return buffer;
Also, your usage of the Enc and Dec is needlessly complex. It's already able to handle the whole file by itself. So to encrypt the file, simply use
var original = File.ReadAllBytes("originalPath");
var enc = Enc(original, rM.Key, rM.IV);
File.WriteAllBytes("encryptedPath", enc);
And to decrypt the file, just use
var enc = File.ReadAllBytes("encryptedPath");
var dec = Dec(enc, rM.Key, rM.IV);
File.WriteAllBytes("decryptedPath", dec);
As you can see, I throw away the fileLength,filepath, chunkSize, and bytesToRead on Enc & Dec, because your current code doesn't actually use them anyway. I've tried the code with short text file on ASCII, Unicode and UTF-8, and with large binary files, all encrypted & decrypted successfully with identical hash on the final decrypted files.
Edit :
Turning the code into direct filestream writing affair actually makes everything so much simpler.
public static void Transform(string source, string target, ICryptoTransform transf)
{
var bufferSize = 65536;
var buffer = new byte[bufferSize];
using (var sourceStream = new FileStream(source, FileMode.Open))
{
using (var targetStream = new FileStream(target, FileMode.OpenOrCreate))
{
using (CryptoStream cs = new CryptoStream(targetStream, transf, CryptoStreamMode.Write))
{
var bytesRead = 0;
do
{
bytesRead = sourceStream.Read(buffer, 0, bufferSize);
cs.Write(buffer, 0, bytesRead);
} while (bytesRead != 0);
}
}
}
}
public static void Enc(string source, byte[] Key, byte[] IV, string target)
{
using (var rijAlg = new AesCng())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
ICryptoTransform encryptor = rijAlg.CreateEncryptor();
Transform(source, target, encryptor);
}
}
public static void Dec(string source, byte[] Key, byte[] IV, string target)
{
using (var rijAlg = new AesCng())
{
rijAlg.Key = Key;
rijAlg.IV = IV;
ICryptoTransform decryptor = rijAlg.CreateDecryptor();
Transform(source, target, decryptor);
}
}
Usage is :
Enc(#"originalPath", key, iv, #"encryptedPath");
Dec(#"encrypedPath", key, iv, #"decryptedPath");

Encrypt/Decrypt Stream in C# using RijndaelManaged

I am trying to encrypt a Generic Stream in C#. Although the program has no problems, the encryption and decryption return blank when converted to strings. Any help is appreciated.
public byte[] AES_Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes)
{
byte[] encryptedBytes = null;
// Set your salt here, change it to meet your flavor:
// The salt bytes must be at least 8 bytes.
byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 10000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CBC;
using (var cs = new CryptoStream(ms, AES.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(bytesToBeEncrypted, 0, bytesToBeEncrypted.Length);
cs.Close();
}
encryptedBytes = ms.ToArray();
}
}
return encryptedBytes;
}
public byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes)
{
byte[] decryptedBytes = null;
// Set your salt here, change it to meet your flavor:
// The salt bytes must be at least 8 bytes.
byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 10000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CBC;
using (var cs = new CryptoStream(ms, AES.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length);
cs.Close();
}
decryptedBytes = ms.ToArray();
}
}
return decryptedBytes;
}
private void Encrypt(Stream input, Stream output, String password)
{
input.Position = 0;
byte[] passwordBytes = Encoding.UTF8.GetBytes(password);
using (var stream = new MemoryStream())
{
byte[] buffer = new byte[2048]; // read in chunks of 2KB
int bytesRead;
while ((bytesRead = input.Read(buffer, 0, buffer.Length)) > 0)
{
stream.Write(buffer, 0, bytesRead);
var tmp = AES_Encrypt(buffer, passwordBytes);
output.Write(tmp, 0, tmp.Length);
}
}
}
private void Decrypt(Stream input, Stream output, String password)
{
input.Position = 0;
byte[] passwordBytes = Encoding.UTF8.GetBytes(password);
using (var stream = new MemoryStream())
{
byte[] buffer = new byte[2048]; // read in chunks of 2KB
int bytesRead;
while ((bytesRead = input.Read(buffer, 0, buffer.Length)) > 0)
{
stream.Write(buffer, 0, bytesRead);
var tmp = AES_Decrypt(buffer, passwordBytes);
output.Write(tmp, 0, tmp.Length);
}
}
}
static void Main(string[] args)
{
Program obj = new Program();
var message = new MemoryStream();
var cipher = new MemoryStream();
string tmp = "This is a test if the encryption is working!";
StreamWriter sw = new StreamWriter(message);
sw.Write(tmp);
obj.Encrypt(message, cipher, "password");
cipher.Position = 0;
message = new MemoryStream();
obj.Decrypt(cipher, message, "password");
using (var memoryStream = new MemoryStream())
{
message.CopyTo(memoryStream);
var bytesdecrypt = memoryStream.ToArray();
string result = Encoding.UTF8.GetString(bytesdecrypt);
Console.WriteLine(result);
Console.ReadLine();
}
}
}
}
The problem is probably when I am reading and writing from and to the streams.
There are many problems with this code.
The reason why nothing is decrypted is because you forgot to reset the message stream before doing message.CopyTo(memoryStream), because CopyTo works from the current position and you haven't changed the position after decryption.
You could reset it with
message.Position = 0;
If arbitrary data is encrypted, AES with some mode of operation like CBC is not enough. We generally need some kind of padding scheme. In C# the default scheme is PKCS#7 padding. Unambiguous padding is always added even when the plaintext is already a multiple of the block size. In those cases a full padding block is added.
Now the problem is that you're reading 2048 byte chunks during encryption and decryption, but the encryption produces 2064 byte ciphertext chunks which must be read as such during decryption. This is a simple fix, but it would be better to use streams all the way instead of encrypting such separate chunks.
You're invoking Rfc2898DeriveBytes for every 2048 byte chunk, but it never changes. Either introduce randomness, but actually using a random salt and random IV, or cache the key. (random salt and random IV are still necessary to reach semantic security)

Error RijndaelManaged, "Padding is invalid and cannot be removed"

I have error from CryptoStream:
Padding is invalid and cannot be removed.
Code
public MemoryStream EncrypteBytes(Stream inputStream, string passPhrase, string saltValue)
{
RijndaelManaged RijndaelCipher = new RijndaelManaged();
RijndaelCipher.Padding = PaddingMode.PKCS7;
RijndaelCipher.Mode = CipherMode.CBC;
byte[] salt = Encoding.ASCII.GetBytes(saltValue);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, salt, "SHA1", 2);
ICryptoTransform Encryptor = RijndaelCipher.CreateEncryptor(password.GetBytes(32), password.GetBytes(16));
MemoryStream memoryStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memoryStream, Encryptor, CryptoStreamMode.Write);
var buffer = new byte[1024];
var read = inputStream.Read(buffer, 0, buffer.Length);
while (read > 0)
{
cryptoStream.Write(buffer, 0, read);
read = inputStream.Read(buffer, 0, buffer.Length);
}
cryptoStream.FlushFinalBlock();
memoryStream.Position = 0;
return memoryStream;
}
// Example usage: DecryptBytes(encryptedBytes, "SensitivePhrase", "SodiumChloride");
public byte[] DecrypteBytes(MemoryStream memoryStream, string passPhrase, string saltValue)
{
RijndaelManaged RijndaelCipher = new RijndaelManaged();
RijndaelCipher.Padding = PaddingMode.PKCS7;
RijndaelCipher.Mode = CipherMode.CBC;
byte[] salt = Encoding.ASCII.GetBytes(saltValue);
PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, salt, "SHA1", 2);
ICryptoTransform Decryptor = RijndaelCipher.CreateDecryptor(password.GetBytes(32), password.GetBytes(16));
CryptoStream cryptoStream = new CryptoStream(memoryStream, Decryptor, CryptoStreamMode.Read);
byte[] plainBytes = new byte[memoryStream.Length];
int DecryptedCount = cryptoStream.Read(plainBytes, 0, plainBytes.Length);
return plainBytes;
}
Use PaddingMode.Zeros to fix problem , Following code:
public byte[] EncryptFile(Stream input, string password, string salt)
{
// Essentially, if you want to use RijndaelManaged as AES you need to make sure that:
// 1.The block size is set to 128 bits
// 2.You are not using CFB mode, or if you are the feedback size is also 128 bits
var algorithm = new RijndaelManaged { KeySize = 256, BlockSize = 128 };
var key = new Rfc2898DeriveBytes(password, Encoding.ASCII.GetBytes(salt));
algorithm.Key = key.GetBytes(algorithm.KeySize / 8);
algorithm.IV = key.GetBytes(algorithm.BlockSize / 8);
algorithm.Padding = PaddingMode.Zeros;
using (Stream cryptoStream = new MemoryStream())
using (var encryptedStream = new CryptoStream(cryptoStream, algorithm.CreateEncryptor(), CryptoStreamMode.Write))
{
CopyStream(input, encryptedStream);
return ReadToEnd(cryptoStream);
}
}
public byte[] DecryptFile(Stream input, Stream output, string password, string salt)
{
// Essentially, if you want to use RijndaelManaged as AES you need to make sure that:
// 1.The block size is set to 128 bits
// 2.You are not using CFB mode, or if you are the feedback size is also 128 bits
var algorithm = new RijndaelManaged { KeySize = 256, BlockSize = 128 };
var key = new Rfc2898DeriveBytes(password, Encoding.ASCII.GetBytes(salt));
algorithm.Key = key.GetBytes(algorithm.KeySize / 8);
algorithm.IV = key.GetBytes(algorithm.BlockSize / 8);
algorithm.Padding = PaddingMode.Zeros;
try
{
using (var decryptedStream = new CryptoStream(output, algorithm.CreateDecryptor(), CryptoStreamMode.Write))
{
CopyStream(input, decryptedStream);
return ReadToEnd(output);
}
}
catch (CryptographicException ex)
{
throw new InvalidDataException("Please supply a correct password");
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
I hop help you.
Please check your pass phrase - it should be same in both methods EncrypteBytes and DecrypteBytes. If both are not same, then it will generate the error.
My problem was I was taking the encryped output in bytes and converting it to a string. The string back to byte array (for decrypting) was not the same. I was using UTF8Encoding, then I tried ASCIIEnconding. Neither worked.
Convert.FromBase64String/ToBase64String worked fine, got rid of the padding issues and actually decrypted the data.
It's work
using (FileStream fs = new FileStream( absolute, FileMode.Open )) {
// create a CryptoStream in read mode
using (CryptoStream cryptoStream = new CryptoStream( fs, decryptor, CryptoStreamMode.Read )) {
int readLength = ( int )fs.Length;
byte[] buffer = new byte[readLength];
cryptoStream.Read( buffer, 0, readLength );
using (MemoryStream ms = new MemoryStream( buffer )) {
BinaryFormatter bf = new BinaryFormatter( );
settings = ( SettingsJson )bf.Deserialize( ms );// Deserialize SettingsJson array
}
}
fs.Close( );
}

How is it possible that Rijndael returns different result from string and byte[]?

Here is my code, first with string:
byte[] concatBytes = Encoding.ASCII.GetBytes(key);
byte[] keyBytes = Encoding.ASCII.GetBytes(key);
for (int i = 0; i < 3; i++)
{
concatBytes = Encrypt(Encoding.ASCII.GetString(concatBytes), keyBytes);
//Console.WriteLine(Transform.Hexa(concatBytes));
}
public byte[] Encrypt(string plainText, byte[] key)
{
byte[] encrypted;
using (var rijndael = new RijndaelManaged())
{
rijndael.Mode = CipherMode.ECB;
rijndael.KeySize = 128;
rijndael.BlockSize = 128;
rijndael.Padding = PaddingMode.Zeros;
rijndael.Key = key;
//rijndael.IV = new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
ICryptoTransform transform = rijndael.CreateEncryptor(rijndael.Key, rijndael.IV);
using (var memoryStream = new MemoryStream())
{
using (var cryptoStream = new CryptoStream(memoryStream, transform, CryptoStreamMode.Write))
{
using (var streamWriter = new StreamWriter(cryptoStream))
{
streamWriter.Write(plainText);
}
encrypted = memoryStream.ToArray();
}
}
}
return encrypted;
}
If i change my method parameter plainText to byte[] than my results are completely different. What am i missing here? Also, we have different results using OpenSSL and Rijndael AES encryption. Any suggestions how i could fix this?
StreamWriter(Stream):
Initializes a new instance of the StreamWriter class for the specified stream by using UTF-8 encoding and the default buffer size.
Since you're using a different encoding (UTF-8 rather than ASCII), it's not surprising that you get different results.

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