Develop Reference

Need help converting c# encryption/Decryption to php

C#
public void start()
{
Constants.APIENCRYPTKEY = Convert.ToBase64String(Encoding.Default.GetBytes(Session(32)));
Constants.APIENCRYPTSALT = Convert.ToBase64String(Encoding.Default.GetBytes(Session(16)));
string results = EncryptService("start");
}
private static string Session(int length)
{
Random random = new Random();
const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
return new string(Enumerable.Repeat(chars, length)
.Select(s => s[random.Next(s.Length)]).ToArray());
}
public static string DecryptService(string value)
{
string message = value;
string password = Encoding.Default.GetString(Convert.FromBase64String(Constants.APIENCRYPTKEY));
SHA256 mySHA256 = SHA256Managed.Create();
byte[] key = mySHA256.ComputeHash(Encoding.ASCII.GetBytes(password));
byte[] iv = Encoding.ASCII.GetBytes(Encoding.Default.GetString(Convert.FromBase64String(Constants.APIENCRYPTSALT)));
string decrypted = DecryptString(message, key, iv);
return decrypted;
}
public static string DecryptString(string cipherText, byte[] key, byte[] iv)
{
Aes encryptor = Aes.Create();
encryptor.Mode = CipherMode.CBC;
encryptor.Key = key;
encryptor.IV = iv;
MemoryStream memoryStream = new MemoryStream();
ICryptoTransform aesDecryptor = encryptor.CreateDecryptor();
CryptoStream cryptoStream = new CryptoStream(memoryStream, aesDecryptor, CryptoStreamMode.Write);
string plainText = String.Empty;
try
{
byte[] cipherBytes = Convert.FromBase64String(cipherText);
cryptoStream.Write(cipherBytes, 0, cipherBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] plainBytes = memoryStream.ToArray();
plainText = Encoding.ASCII.GetString(plainBytes, 0, plainBytes.Length);
}
finally
{
memoryStream.Close();
cryptoStream.Close();
}
return plainText;
}
public static string EncryptService(string value)
{
string message = value;
string password = Encoding.Default.GetString(Convert.FromBase64String(Constants.APIENCRYPTKEY));
SHA256 mySHA256 = SHA256Managed.Create();
byte[] key = mySHA256.ComputeHash(Encoding.ASCII.GetBytes(password));
byte[] iv = Encoding.ASCII.GetBytes(Encoding.Default.GetString(Convert.FromBase64String(Constants.APIENCRYPTSALT)));
string encrypted = EncryptString(message, key, iv);
int property = Int32.Parse((OnProgramStart.AID.Substring(0, 2)));
string final = encrypted + Security.Obfuscate(property);
return final;
}
public static string EncryptString(string plainText, byte[] key, byte[] iv)
{
Aes encryptor = Aes.Create();
encryptor.Mode = CipherMode.CBC;
encryptor.Key = key;
encryptor.IV = iv;
MemoryStream memoryStream = new MemoryStream();
ICryptoTransform aesEncryptor = encryptor.CreateEncryptor();
CryptoStream cryptoStream = new CryptoStream(memoryStream, aesEncryptor, CryptoStreamMode.Write);
byte[] plainBytes = Encoding.ASCII.GetBytes(plainText);
cryptoStream.Write(plainBytes, 0, plainBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
string cipherText = Convert.ToBase64String(cipherBytes, 0, cipherBytes.Length);
return cipherText;
}
This is what I got so far in PHP
function decrypt_string($msg='', $salt='', $key='')
{
$key = utf8_encode(base64_decode($key));
$key = hash('sha256', $key);
$salt = utf8_encode(base64_decode($salt));
$salt = EncodingASCII($salt);
$method = 'aes-256-cbc';
$msg = openssl_decrypt($msg, $method, $key, OPENSSL_RAW_DATA, $salt);
return $msg;
}
The encrypt and decrypt works perfect on c#, but I can't get it to decrypt on php. Haven't attempted to make the encrypt in php yet. My c# application calls on the php script with a encrypted data and needs to be decrypted on the php side then encrypted data sent back to the c# application.

How implement Php's openssl_encrypt method in c#?

as in the title, I need to implement in my C# code the equivalent of php's openssl_encrypt method, because I need to call a service on a php page, but we work with c#.
The php code is this:
$textToEncrypt = "test";
$algo = "AES256";
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($algo));
$key = "1234567890987654"; //Not this key, but just same length
$parametri_enc = openssl_encrypt($textToEncrypt , $algo, $key, 0, $iv);
$iv = bin2hex($iv);
I tried many thing, actually my code is:
string textToEncrypt = "test";
string secretCode = "1234567890987654"
// Create sha256 hash
SHA256 mySHA256 = SHA256Managed.Create();
byte[] key = mySHA256.ComputeHash(Encoding.ASCII.GetBytes(secretCode));
// Create secret IV
byte[] iv = new byte[16];
RandomNumberGenerator generator = RandomNumberGenerator.Create();
generator.GetBytes(iv);
string encryptedText = EncryptString(textToEncrypt, key, iv);
// And I try to port also the bin2hex method
var sb = new StringBuilder();
foreach (byte b in iv)
{
sb.AppendFormat("{0:x2}", b);
}
var tokenBytesHex = sb.ToString();
And the method EncryptString is
public static string EncryptString(string plainText, byte[] key, byte[] iv)
{
//Instantiate a new Aes object to perform string symmetric encryption
Aes encryptor = Aes.Create();
encryptor.Mode = CipherMode.CBC;
// Set key and IV
byte[] aesKey = new byte[32];
Array.Copy(key, 0, aesKey, 0, 32);
encryptor.Key = aesKey;
encryptor.IV = iv;
// Instantiate a new MemoryStream object to contain the encrypted bytes
MemoryStream memoryStream = new MemoryStream();
// Instantiate a new encryptor from our Aes object
ICryptoTransform aesEncryptor = encryptor.CreateEncryptor();
// Instantiate a new CryptoStream object to process the data and write it to the
// memory stream
CryptoStream cryptoStream = new CryptoStream(memoryStream, aesEncryptor, CryptoStreamMode.Write);
// Convert the plainText string into a byte array
byte[] plainBytes = Encoding.ASCII.GetBytes(plainText);
// Encrypt the input plaintext string
cryptoStream.Write(plainBytes, 0, plainBytes.Length);
// Complete the encryption process
cryptoStream.FlushFinalBlock();
// Convert the encrypted data from a MemoryStream to a byte array
byte[] cipherBytes = memoryStream.ToArray();
// Close both the MemoryStream and the CryptoStream
memoryStream.Close();
cryptoStream.Close();
// Convert the encrypted byte array to a base64 encoded string
string cipherText = Convert.ToBase64String(cipherBytes, 0, cipherBytes.Length);
// Return the encrypted data as a string
return cipherText;
}
I tried many variation about this porting (that I've found on internet), but without result. If I use a correct encrypted string from my code, I can call the service, so it is working. I need only to encrypt correctly that string, but until now, I've failed

Ok i solved my own problem. I'll share it so if anyone has the same problem, this could work. Basically I saw a decryption c# code here so I update my code in this way
First, I pass my secretCode in string format instead of byte[]
So i changed my method signature in this way:
public static string EncryptString(string plainText, string secretcode, byte[] iv)
and inside I changed the way I manipulate the secretCode (passphrase in php equivalent method)
// Set key and IV
var aesKey = Encoding.ASCII.GetBytes(secretcode);
//pad key out to 32 bytes (256bits) if its too short
if (aesKey.Length < 32)
{
var paddedkey = new byte[32];
Buffer.BlockCopy(aesKey, 0, paddedkey, 0, aesKey.Length);
aesKey = paddedkey;
}
So it worked! No other change, just this two small change from my previous post
Updated method
public static string EncryptString(string plainText, string secretcode, byte[] iv)
{
// Instantiate a new Aes object to perform string symmetric encryption
Aes encryptor = Aes.Create();
encryptor.Mode = CipherMode.CBC;
// Set key and IV
var aesKey = Encoding.ASCII.GetBytes(secretcode);
//pad key out to 32 bytes (256bits) if its too short
if (aesKey.Length < 32)
{
var paddedkey = new byte[32];
Buffer.BlockCopy(aesKey, 0, paddedkey, 0, aesKey.Length);
aesKey = paddedkey;
}
encryptor.Key = aesKey;
encryptor.IV = iv;
// Instantiate a new MemoryStream object to contain the encrypted bytes
MemoryStream memoryStream = new MemoryStream();
// Instantiate a new encryptor from our Aes object
ICryptoTransform aesEncryptor = encryptor.CreateEncryptor();
// Instantiate a new CryptoStream object to process the data and write it to the
// memory stream
CryptoStream cryptoStream = new CryptoStream(memoryStream, aesEncryptor, CryptoStreamMode.Write);
// Convert the plainText string into a byte array
byte[] plainBytes = Encoding.ASCII.GetBytes(plainText);
// Encrypt the input plaintext string
cryptoStream.Write(plainBytes, 0, plainBytes.Length);
// Complete the encryption process
cryptoStream.FlushFinalBlock();
// Convert the encrypted data from a MemoryStream to a byte array
byte[] cipherBytes = memoryStream.ToArray();
// Close both the MemoryStream and the CryptoStream
memoryStream.Close();
cryptoStream.Close();
// Convert the encrypted byte array to a base64 encoded string
string cipherText = Convert.ToBase64String(cipherBytes, 0, cipherBytes.Length);
// Return the encrypted data as a string
return cipherText;
}

xamarin Android encryption GetBytes Method difference with C#

I have an App in Visual Studio 2013, with password Encryptation Methods, and i need to migrate it to Xamarin Android.
The problem I had is that encryptation method in Xamarin gives a different encryptation string.
The difference is in GetBytes Method.
Here is part of my code.
public static string Encript(string ptexto, string pClave)
{
return Encript2(ptexto, pClave + "pass75dc#avz10", "s#lAvz", "MD5", 1, "#1B2c3D4e5F6g7H8", 128);
}
private static string Encript2(string textoQueEncriptaremos, string passBase, string saltValue, string hashAlgorithm, int passwordIterations, string initVector, int keySize)
{
byte[] initVectorBytes = Encoding.ASCII.GetBytes(initVector);
byte[] saltValueBytes = Encoding.ASCII.GetBytes(saltValue);
byte[] plainTextBytes = Encoding.UTF8.GetBytes(textoQueEncriptaremos);
PasswordDeriveBytes password = new PasswordDeriveBytes(passBase,saltValueBytes, hashAlgorithm, passwordIterations);
byte[] keyBytes = password.GetBytes(keySize / 8);
RijndaelManaged symmetricKey = new RijndaelManaged()
{
Mode = CipherMode.CBC
};
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes,initVectorBytes);
MemoryStream memoryStream = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor,CryptoStreamMode.Write);
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherTextBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
string cipherText = Convert.ToBase64String(cipherTextBytes);
return cipherText;
}
The line that make the difference is
byte[] keyBytes = password.GetBytes(keySize / 8);
I can not change my Encryptation in my c# Applicaction, Is there a way to obtain the same result in Xamarin?

From documentation you can check, it's normal you getting different byte array, GetByte() always return RANDOM key bytes. more
GetBytes(Int32) : Byte[]
Returns pseudo-random key bytes.

Padding is invalid and cannot be removed with Rijndael

when i use this code to encrypt and decrypt i got an error said
Padding is invalid and cannot be removed.
any idea
public static class Crypto
{
private static readonly byte[] initVectorBytes = Encoding.ASCII.GetBytes("tu89geji340t89u2");
// This constant is used to determine the keysize of the encryption algorithm.
private const int keysize = 256;
public static string Encrypt(string plainText, string passPhrase)
{
byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);
using (PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null))
{
byte[] keyBytes = password.GetBytes(keysize / 8);
using (RijndaelManaged symmetricKey = new RijndaelManaged())
{
symmetricKey.Mode = CipherMode.CBC;
using (ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes))
{
using (MemoryStream memoryStream = new MemoryStream())
{
using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
{
cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
cryptoStream.FlushFinalBlock();
byte[] cipherTextBytes = memoryStream.ToArray();
return Convert.ToBase64String(cipherTextBytes);
}
}
}
}
}
}
public static string Decrypt(string cipherText, string passPhrase)
{
byte[] cipherTextBytes = Convert.FromBase64String(cipherText);
using (PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null))
{
byte[] keyBytes = password.GetBytes(keysize / 8);
using (RijndaelManaged symmetricKey = new RijndaelManaged())
{
symmetricKey.Mode = CipherMode.CBC;
using (ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes))
{
using (MemoryStream memoryStream = new MemoryStream(cipherTextBytes))
{
using (CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
{
byte[] plainTextBytes = new byte[cipherTextBytes.Length];
int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
}
}
}
}
}
}
}

I tried the following using your methods and it worked fine:
var passPhrase = "123456";
var e = Encrypt("testtesttesttest", passPhrase);
Console.WriteLine(e); // YEtSJshcn686ZO+JlEQ48ap/odhuvIGalbAT1XhinqQ=
var d = Decrypt(e, passPhrase);
Console.WriteLine(d); // testtesttesttest
This suggests that you're either passing a different passPhrase to Decrypt() to the one you passed to Encrypt(), or that you are somehow corrupting the ciphertext prior to decryption. (Are you perhaps calling Decrypt with the ciphertext and passphrase parameters reversed?)
It's also worth noting that essentially everything in the comments at the top of your code is wrong:
You're not passing any salt to PasswordDeriveBytes.
The size of the IV must be equal to the block size (16 bytes), it is unrelated to the key size used.
Passing a 16 character string through Encoding.ASCII.GetBytes() results in a 16 byte output, not 32 bytes. (This rather coincidentally means that your initVectorBytes is in fact the correct length for the IV).
Furthermore, PasswordDeriveBytes is deprecated and should not be used. You should be using Rfc2898DeriveBytes instead, and you should be using a proper salt value. The IV should also not be a static value, and definitely not one derived from an ASCII string!

C# RijndaelManaged cryptographic storage key

my doubt is about the key to decrypt a encrypted string, without the same key used to encrypt the string i dont get the original string ok, but I need to protect this key not use her in hardcode because any hacker could decompiling a dll and see this key, if I to store this key in any archive, the hacker could copy this archive and my method and decrypt my text, how can i prevent this attack? following my code implementation, here the salt and key are static I'm trying to think in anyway to safe these datas
private static byte[] salt = new byte[255];
private static byte[] key;
internal static string EncryptString(string InputText)
{
System.Security.Cryptography.RijndaelManaged RijndaelCipher =
new System.Security.Cryptography.RijndaelManaged();
RNGCryptoServiceProvider rcs = new RNGCryptoServiceProvider();
rcs.GetBytes(salt);
key = RijndaelCipher.Key;
byte[] plainText = System.Text.Encoding.Unicode.GetBytes(InputText);
System.Security.Cryptography.PasswordDeriveBytes SecretKey =
new System.Security.Cryptography.PasswordDeriveBytes(RijndaelCipher.Key, salt);
System.Security.Cryptography.ICryptoTransform Encryptor =
RijndaelCipher.CreateEncryptor(SecretKey.GetBytes(32), SecretKey.GetBytes(16));
System.IO.MemoryStream memoryStream = new System.IO.MemoryStream();
System.Security.Cryptography.CryptoStream cryptoStream =
new System.Security.Cryptography.CryptoStream(memoryStream, Encryptor, CryptoStreamMode.Write);
cryptoStream.Write(plainText, 0, plainText.Length);
cryptoStream.FlushFinalBlock();
byte[] CipherBytes = memoryStream.ToArray();
memoryStream.Close();
cryptoStream.Close();
string EncryptedData = Convert.ToBase64String(CipherBytes);
return EncryptedData;
}
internal static string DecryptString(string text)
{
System.Security.Cryptography.RijndaelManaged RijndaelCipher =
new System.Security.Cryptography.RijndaelManaged();
byte[] EncryptedData = Convert.FromBase64String(text);
System.Security.Cryptography.PasswordDeriveBytes SecretKey =
new System.Security.Cryptography.PasswordDeriveBytes(RijndaelCipher.Key, salt);
ICryptoTransform Decryptor =
RijndaelCipher.CreateDecryptor(SecretKey.GetBytes(32), SecretKey.GetBytes(16));
System.IO.MemoryStream memoryStream = new System.IO.MemoryStream(EncryptedData);
CryptoStream cryptoStream = new CryptoStream(memoryStream, Decryptor, CryptoStreamMode.Read);
byte[] PlainText = new byte[EncryptedData.Length];
int DecryptedCount = cryptoStream.Read(PlainText, 0, PlainText.Length);
memoryStream.Close();
cryptoStream.Close();
string DecryptedData = Encoding.Unicode.GetString(PlainText, 0, DecryptedCount);
return DecryptedData;
}
#endregion
}