Develop Reference

Is it possible to run a PHP function in .NET?

I'm trying to decrypt AES-128 CBC strings in C# but with no success (tried every decrypt method I found on internet for this type of encryption).
The only way I got a result was decrypting those strings in PHP using this code:
<?php
$crypto_data = hex2bin($crypto_data_hex);
$real_data = openssl_decrypt($crypto_data,
'AES-128-CBC',
'23d854ce7364b4f7',
OPENSSL_RAW_DATA,
'23d854ce7364b4f7');
?>
So, is there a way to run this PHP code in .NET (using a PHP.dll library or something similar) ? Or is there a real equivalent method for this operation in .NET C# ?
Thank you

The question seems to boil down to writing C# function that is equivalent to PHP function.
Try this code:
public class Program
{
public static byte[] HexToBytes(string hex)
{
int numberChars = hex.Length;
byte[] bytes = new byte[numberChars / 2];
for (int i = 0; i < numberChars; i += 2)
{
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
}
return bytes;
}
static string Decrypt(byte[] cipherText, byte[] key, byte[] iv)
{
string plaintext;
AesManaged aes = new AesManaged
{
Mode = CipherMode.CBC,
Padding = PaddingMode.PKCS7,
BlockSize = 128,
Key = key,
IV = iv
};
using (aes)
{
ICryptoTransform decryptor = aes.CreateDecryptor();
using (MemoryStream ms = new MemoryStream(cipherText))
{
using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
{
using (StreamReader reader = new StreamReader(cs))
{
plaintext = reader.ReadToEnd();
}
}
}
}
return plaintext;
}
public static void Main()
{
string crypto_data_hex = "00965fa56e761b11d37b887f98e6bcc2"; // paste $crypto_data_hex value here
string sKey = "23d854ce7364b4f7";
string sIv = "23d854ce7364b4f7";
byte[] encrypted = HexToBytes(crypto_data_hex);
byte[] key = Encoding.ASCII.GetBytes(sKey);
byte[] iv = Encoding.ASCII.GetBytes(sIv);
string decrypted = Decrypt(encrypted, key, iv);
Console.WriteLine(decrypted);
}
}

Unrecognized unicode result from AES decryption

I try to build simple AES encryption helper to encrypt/decrypt some strings
Fist, I have an issue with Padding mode wherein decryption it only accepts if Zero otherwise an error about padding occurs!
The second issue is when I try to encrypt simple string "Hello World," it got encrypted, and I have the base64 string, but when trying to decrypt, there's no error, but a weird unknown character is shown! like 㡲啁䎰廾ử靱힩㡲啁䎰廾ử靱힩
My code:
private static int keySizes = 256;
private static int blockSize = 128;
private static PaddingMode pMode = PaddingMode.Zeros;
private static CipherMode cMode = CipherMode.ECB;
private static byte[] key = GenEncryptionKey();
private const string passphrase = #"StartYourMorningWithASmile";
private static byte[] GenEncryptionKey()
{
HashAlgorithm hash = MD5.Create();
return hash.ComputeHash(Encoding.Unicode.GetBytes(passphrase));
}
private static AesManaged CreateCryptor()
{
AesManaged cryptor = new AesManaged();
cryptor.KeySize = keySizes;
cryptor.BlockSize = blockSize;
cryptor.Padding = pMode;
cryptor.Key = key;
cryptor.Mode = cMode;
cryptor.GenerateIV();
return cryptor;
}
public static string EncryptParams(string reqVal)
{
string cipherText = "";
if (string.IsNullOrEmpty(reqVal) || reqVal.Length < 1)
throw new ArgumentNullException();
byte[] plainBytes = Encoding.Unicode.GetBytes(reqVal);
using (var cryptor = CreateCryptor())
{
ICryptoTransform encryptor = cryptor.CreateEncryptor();
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
cs.Write(plainBytes, 0, plainBytes.Length);
}
byte[] cipherBytes = ms.ToArray();
cipherText = Convert.ToBase64String(cipherBytes);
}
cryptor.Clear();
}
return cipherText;
}
public static string DecryptParams(string resVal)
{
var data = Convert.FromBase64String(resVal);
byte[] cipherBytes = new byte[data.Length];
string plainText = "";
using (var crypto = CreateCryptor())
{
ICryptoTransform Dec = crypto.CreateDecryptor();
using (MemoryStream ms = new MemoryStream())
{
using (var cs = new CryptoStream(ms, Dec, CryptoStreamMode.Write))
{
cs.Write(cipherBytes, 0, cipherBytes.Length);
plainText = Encoding.Unicode.GetString(ms.ToArray());
}
}
crypto.Clear();
}
return plainText;
}

UPDATE 1:
Please set also the IV yourself to achieve successful decryption, as #maarten-bodewes pointed out. I missed that part and the decryption somehow worked (?) with your existing code, but you always should provide the same key and IV to a symmetric encryption algorithm to have it work both ways.
ORIGINAL ANSWER:
Your decryption fails (produces incorrect results) because you implemented the decryption part incorrectly (by using CryptoStreamMode.Write instead of CryptoStreamMode.Read) and besides feeding the decryption stream all zero bytes
At the point of execution of
cs.Write(cipherBytes, 0, cipherBytes.Length);
the variable cipherBytes is all zero. The real encrypted buffer is in the data variable which you only use to set the length of cipherBytes
So change your decryption method to this.
BONUS: After correcting the decryption part, you can specify the padding as you wish! I tested with PKCS7 and it is ok.
public static string DecryptParams(string resVal)
{
var cipherBytes = Convert.FromBase64String(resVal);
string plainText = "";
using (var crypto = CreateCryptor())
{
ICryptoTransform Dec = crypto.CreateDecryptor();
using (MemoryStream ms = new MemoryStream(cipherBytes))
{
using (var cs = new CryptoStream(ms, Dec, CryptoStreamMode.Read))
{
byte[] decryptBlock = new byte[4096];
MemoryStream decryptStream = new MemoryStream();
int readBytes;
while ((readBytes = cs.Read(decryptBlock, 0, 4096)) > 0)
{
decryptStream.Write(decryptBlock, 0, readBytes);
}
plainText = Encoding.Unicode.GetString(decryptStream.ToArray());
}
}
crypto.Clear();
}
return plainText;
}
Hope this helps.

Thanks to Oguz
Below is my description method after edit
public static string DecryptParams(string resVal)
{
var data = Convert.FromBase64String(resVal);
byte[] cipherBytes = new byte[data.Length];
string plainText = "";
using (var crypto = CreateCryptor())
{
ICryptoTransform Dec = crypto.CreateDecryptor();
using (MemoryStream ms = new MemoryStream(data))
{
using (var cs = new CryptoStream(ms, Dec, CryptoStreamMode.Read))
{
cs.Read(cipherBytes, 0, cipherBytes.Length);
plainText = Encoding.Unicode.GetString(cipherBytes.ToArray());
}
}
crypto.Clear();
}
return plainText;
}
one more thing about the return result after the decryption I got the original string plus \0\0\0\0 so I use myString.TrimEnd('\0') to solve that.

Get IV from Encrypted text to use in decrypt method

I am trying to encrypt and decrypt using AES256 algorithm, I have the following code.
public string Encrypt(string dataToEncrypt, string key)
{
if (dataToEncrypt == null || dataToEncrypt.Length <= 0)
throw new ArgumentNullException("plainText");
if (key == null || key.Length <= 0)
throw new ArgumentNullException("Key");
var iv = GenerateRandomNumber(16);
using (var aes = new AesCryptoServiceProvider())
{
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
aes.Key = Convert.FromBase64String(key);
aes.IV = iv;
byte[] data = Encoding.UTF8.GetBytes(dataToEncrypt);
using (var memoryStream = new MemoryStream())
{
var cryptoStream = new CryptoStream(memoryStream,
aes.CreateEncryptor(),
CryptoStreamMode.Write);
cryptoStream.Write(data, 0, data.Length);
cryptoStream.FlushFinalBlock();
return Convert.ToBase64String(memoryStream.ToArray());
}
}
}
public string DecryptReturnsString(string dataToDecrypt, string key)
{
if (dataToDecrypt == null || dataToDecrypt.Length <= 0)
throw new ArgumentNullException("dataToDecrypt");
if (key == null || key.Length <= 0)
throw new ArgumentNullException("Key");
using (var aes = new AesCryptoServiceProvider())
{
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
aes.Key = Convert.FromBase64String(key);
byte[] data= Convert.FromBase64String(dataToDecrypt);
aes.IV = getIV(data);
using (var memoryStream = new MemoryStream())
{
var cryptoStream = new CryptoStream(memoryStream, aes.CreateDecryptor(),
CryptoStreamMode.Write);
cryptoStream.Write(data, 0, data.Length);
cryptoStream.FlushFinalBlock();
var decryptBytes = Encoding.UTF8.GetString(memoryStream.ToArray());
return decryptBytes;
}
}
}
public byte[] GenerateRandomNumber(int length)
{
using (var randomNumberGenerator = new RNGCryptoServiceProvider())
{
var randomNumber = new byte[length];
randomNumberGenerator.GetBytes(randomNumber);
return randomNumber;
}
}
private static byte[] getIV(byte[] arr)
{
byte[] IV = new byte[16];
Array.Copy(arr, 0, IV, 0, 16);
return IV;
}
Here I am trying to Get the IV from the encrypted string, but the originally generated IV and the extracted IV are different when I was debugging, so its giving me this exception, "Padding is invalid and cannot be removed."
Can anyone please look at my GetIV() method and let me know where I am doing wrong.

There are two issues.
Seems you are not sending IV along your ciphertext (it is not done itself) . Common practice is prepending the IV to the the ciphertext. So as Robert commented, you can write IVto the memory stream directly prior encryption
when decrypting, you can read the IV (first bytes of your data, but decrypt only the rest (sub-array 16 .. length )

IV in CBC mode of operation the IV must be sent as unencrypted, otherwise, you cannot decrypt the first block, the rest can be decrypted. There is no security issue in this. For the CBC the crucial about the IV is that it must be unpredictable.
as Robert said, prepend it to the beginning of the stream.
see
var mergedStream = new MergedStream(new Stream
{
new MemoryStream(iv),
cryptoStream,
}

Why RijndaelManaged returns junk data after encryption?

I have taken the decrypt code from http://msdn.microsoft.com/en-us/library/system.security.cryptography.cryptostream.aspx and modified it as follows below. I have an encrypted example, and it works just fine while decoding. But when using the encryption function, it returns junk string with strange symbols. below are the functions of encrypt/decrypt.
An example of encrypted string "hey" : "???U?b???z?Y???"
When decoded again: "ûc{ÁpÅ`ñ""Â"
I'm using this code to convert the byte array to string:
private string ByteArrayToString(byte[] input)
{
ASCIIEncoding dec = new ASCIIEncoding();
return dec.GetString(input);
}
here are the encrypt/decrypt functions. the decryption function is working fine.
private string DecryptStringFromBytesAes(byte[] cipherText, byte[] Key, byte[] IV)
{
// Check arguments.
if (cipherText == null || cipherText.Length <= 0)
throw new ArgumentNullException("cipherText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
// Declare the string used to hold
// the decrypted text.
string plaintext = null;
// Create an RijndaelManaged object
// with the specified key and IV.
using (RijndaelManaged aesAlg = new RijndaelManaged())
{
aesAlg.Key = Key;
aesAlg.Padding = PaddingMode.Zeros;
aesAlg.Mode = CipherMode.ECB;
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for decryption.
using (MemoryStream msDecrypt = new MemoryStream(cipherText))
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
{
// Read the decrypted bytes from the decrypting stream
// and place them in a string.
plaintext = srDecrypt.ReadToEnd();
}
}
}
}
return plaintext;
}
private byte[] EncryptStringToBytesAes(string plainText, byte[] Key, byte[] IV)
{
// Check arguments.
if (plainText == null || plainText.Length <= 0)
throw new ArgumentNullException("plainText");
if (Key == null || Key.Length <= 0)
throw new ArgumentNullException("Key");
byte[] encrypted;
// Create an RijndaelManaged object
// with the specified key and IV.
using (RijndaelManaged aesAlg = new RijndaelManaged())
{
aesAlg.Key = Key;
aesAlg.Padding = PaddingMode.Zeros;
aesAlg.Mode = CipherMode.ECB;
// Create a decrytor to perform the stream transform.
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for encryption.
using (MemoryStream msEncrypt = new MemoryStream())
{
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
//Write all data to the stream.
swEncrypt.Write(plainText);
}
encrypted = msEncrypt.ToArray();
}
}
}
return encrypted;
}

What you observe is the problem of mapping arbitrary bytes (in the range 0-255) to characters. Meaningful characters are only in the range 32-255 or even only 32-127 (ASCII). Values below 32 are the so-called non-printable characters and values above 127 are dependent on the character encoding you are using. That's why the crypted text looks like junk. Mast crypto-systems therefore transform the bytes into the sensible ASCII-range. One such algorithm is BASE64. So mangling the crypted bytes through BASE64 gives characters that are all printable and that will go without problems through e-mail. Before decrypting you then have to undo the BASE64 encoding.
Another way to make the encrypted result look better is to show the hexa-decimal representation of it. For example if you have a byte value of 15 you print 0F. You may use this to represent your byte array in hex:
private string ByteArrayToHexString(byte[] data)
{
return String.Concat(data.Select(b => b.ToString("x2")));
}

In order to have your output as a hexadecimal encoding of the data, follow the methods found here. I modified them slightly to be extension methods:
public static string ToHexString(this byte[] bytes)
{
return bytes == null ? string.Empty : BitConverter.ToString(bytes).Replace("-", string.Empty);
}
public static byte[] FromHexString(this string hexString)
{
if (hexString == null)
{
return new byte[0];
}
var numberChars = hexString.Length;
var bytes = new byte[numberChars / 2];
for (var i = 0; i < numberChars; i += 2)
{
bytes[i / 2] = Convert.ToByte(hexString.Substring(i, 2), 16);
}
return bytes;
}

Encrypted strings will look like garble. The way to test if the encryption is working correctly is to pass your string back through decrypt. If it works at decrypting then you know the string is correct despite looking like garbage to you.

Rijndael Encryption issues

I don't know what I'm doing wrong but I've been trying to get this thing working for about 4 hours now and I just can't get it to work... this just gives me the error: "Please suppy a correct password" when I try to decrypt.
Encryption seems to work fine though.
Any suggestions? :<
using System;
using System.Text;
using System.Security.Cryptography;
using System.IO;
using System.Security;
using AesApp.Rijndael;
using System.Linq;
internal class FileEncryption
{
private static string password = pw;
internal static void Encrypt(string inputfile, string outputfile)
{
byte[] encryptedPassword;
// Create a new instance of the RijndaelManaged
// class. This generates a new key and initialization
// vector (IV).
using (var algorithm = new RijndaelManaged())
{
algorithm.KeySize = 256;
algorithm.BlockSize = 128;
// Encrypt the string to an array of bytes.
encryptedPassword = Cryptology.EncryptStringToBytes(
password, algorithm.Key, algorithm.IV);
}
string chars = encryptedPassword.Aggregate(string.Empty, (current, b) => current + b.ToString());
Cryptology.EncryptFile(#inputfile, #outputfile, chars);
}
internal static void Decrypt(string #inputfile, string #outputfile)
{
byte[] encryptedPassword;
// Create a new instance of the RijndaelManaged
// class. This generates a new key and initialization
// vector (IV).
using (var algorithm = new RijndaelManaged())
{
algorithm.KeySize = 256;
algorithm.BlockSize = 128;
// Encrypt the string to an array of bytes.
encryptedPassword = Cryptology.EncryptStringToBytes(
password, algorithm.Key, algorithm.IV);
}
string chars = encryptedPassword.Aggregate(string.Empty, (current, b) => current + b.ToString());
Cryptology.DecryptFile(#inputfile, #outputfile, chars);
}
}
Reindael.cs
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
namespace AesApp.Rijndael
{
internal sealed class Cryptology
{
private const string Salt = "d5fg4df5sg4ds5fg45sdfg4";
private const int SizeOfBuffer = 1024 * 8;
internal static byte[] EncryptStringToBytes(string plainText, byte[] key, byte[] iv)
{
// Check arguments.
if (plainText == null || plainText.Length <= 0)
{
throw new ArgumentNullException("plainText");
}
if (key == null || key.Length <= 0)
{
throw new ArgumentNullException("key");
}
if (iv == null || iv.Length <= 0)
{
throw new ArgumentNullException("key");
}
byte[] encrypted;
// Create an RijndaelManaged object
// with the specified key and IV.
using (var rijAlg = new RijndaelManaged())
{
rijAlg.Key = key;
rijAlg.IV = iv;
// Create a decrytor to perform the stream transform.
ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);
// Create the streams used for encryption.
using (var msEncrypt = new MemoryStream())
{
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (var swEncrypt = new StreamWriter(csEncrypt))
{
//Write all data to the stream.
swEncrypt.Write(plainText);
}
encrypted = msEncrypt.ToArray();
}
}
}
// Return the encrypted bytes from the memory stream.
return encrypted;
}
internal static string DecryptStringFromBytes(byte[] cipherText, byte[] key, byte[] iv)
{
// Check arguments.
if (cipherText == null || cipherText.Length <= 0)
throw new ArgumentNullException("cipherText");
if (key == null || key.Length <= 0)
throw new ArgumentNullException("key");
if (iv == null || iv.Length <= 0)
throw new ArgumentNullException("key");
// Declare the string used to hold
// the decrypted text.
string plaintext;
// Create an RijndaelManaged object
// with the specified key and IV.
using (var rijAlg = new RijndaelManaged())
{
rijAlg.Key = key;
rijAlg.IV = iv;
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
// Create the streams used for decryption.
using (var msDecrypt = new MemoryStream(cipherText))
{
using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (var srDecrypt = new StreamReader(csDecrypt))
{
// Read the decrypted bytes from the decrypting stream
// and place them in a string.
plaintext = srDecrypt.ReadToEnd();
}
}
}
}
return plaintext;
}
internal static void EncryptFile(string inputPath, string outputPath, string password)
{
var input = new FileStream(inputPath, FileMode.Open, FileAccess.Read);
var output = new FileStream(outputPath, FileMode.OpenOrCreate, FileAccess.Write);
// 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);
using (var encryptedStream = new CryptoStream(output, algorithm.CreateEncryptor(), CryptoStreamMode.Write))
{
CopyStream(input, encryptedStream);
}
}
internal static void DecryptFile(string inputPath, string outputPath, string password)
{
var input = new FileStream(inputPath, FileMode.Open, FileAccess.Read);
var output = new FileStream(outputPath, FileMode.OpenOrCreate, FileAccess.Write);
// 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);
try
{
using (var decryptedStream = new CryptoStream(output, algorithm.CreateDecryptor(), CryptoStreamMode.Write))
{
CopyStream(input, decryptedStream);
}
}
catch (CryptographicException)
{
throw new InvalidDataException("Please suppy a correct password");
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
private static void CopyStream(Stream input, Stream output)
{
using (output)
using (input)
{
byte[] buffer = new byte[SizeOfBuffer];
int read;
while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
{
output.Write(buffer, 0, read);
}
}
}
}
}

Not entirely sure, but I think I remember a time when 2 successive calls to encryption gave 2 different results.
Therefore, your two successive calls to EncryptStringToBytes may give 2 different passwords : one for encryption and one for decryption... and this cause the failure.
I am not sure these encryptions are necessary... if you have a password hardcoded, it is always possible to anyone to generate other strings that depend on nothing else. You should use this password directly, instead of crypting it a first time:
internal static void Encrypt(string inputfile, string outputfile)
{
Cryptology.EncryptFile(inputfile, outputfile, password);
}
internal static void Decrypt(string inputfile, string outputfile)
{
Cryptology.DecryptFile(inputfile, outputfile, password);
}

Your Encrypt function seems to be exactly equal to your decrypt function.
Also, why are you converting all bytes to strings and concatenate them? This transformation is not reversible.

string chars = encryptedPassword.Aggregate(string.Empty, (current, b) => current + b.ToString());
Cryptology.EncryptFile(#inputfile, #outputfile, chars);
The Aggregate() function is the cause. It is creating different values each time you run your application.