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Convert "AES-128-ECB" encryption code from PHP to C#

I have a requirement where I need to convert some PHP code to C#.. following is the PHP Code that needs to be converted:
$data = "Hello World!";
$key = "RTc0MDkwMEEwMDYxQjc4Mg=="
$encRaw = openssl_encrypt($data, 'AES-128-ECB', $key, OPENSSL_RAW_DATA);
To convert this openssl encryption, I am using below C# code:
static byte[] EncryptStringToBytes_Aes(string plainText, byte[] Key)
{
// 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 Aes object
// with the specified key and IV.
using (Aes aesAlg = Aes.Create())
{
aesAlg.Key = Key;
//aesAlg.IV = IV;
// Create an encryptor 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 the encrypted bytes from the memory stream.
return encrypted;
}
But somehow this is not giving me same result that PHP function is returning.
Can someone please help me to identify the issue in my code? Or suggest me what other changes should I do in my code so that I get the similar result that PHP function is returning.

Build an encrypted key without '=' characters

I came across to this old C# code and I was wondering if with .NET Framework 4.5 is there something more elegant and compact to do the same thing: encrypt a text avoiding '=' chars in the result.
Thanks.
EDIT: in addition where the number 40 comes from and why longer text does not need to be processed?
public static string BuildAutoLoginUrl(string username)
{
// build a plain text string as username#AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
if (username.Length < 40)
{
//cycle to avoid '=' character at the end of the encrypted string
int len = username.Length;
do
{
if (len == username.Length)
{
username += "#";
}
username += "A";
len++;
} while (len < 41);
}
return #"http://www.domain.com/Account/AutoLogin?key=" + EncryptStringAES(username, sharedKey);
}
public static string EncryptStringAES(string plainText, string sharedSecret)
{
if (string.IsNullOrEmpty(plainText))
throw new ArgumentNullException("plainText");
if (string.IsNullOrEmpty(sharedSecret))
throw new ArgumentNullException("sharedSecret");
string outStr = null; // Encrypted string to return
RijndaelManaged aesAlg = null; // RijndaelManaged object used to encrypt the data.
try
{
// generate the key from the shared secret and the salt
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, _salt);
// Create a RijndaelManaged object
// with the specified key and IV.
aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize/8);
aesAlg.IV = key.GetBytes(aesAlg.BlockSize/8);
// 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);
}
}
outStr = Convert.ToBase64String(msEncrypt.ToArray());
}
}
finally
{
// Clear the RijndaelManaged object.
if (aesAlg != null)
aesAlg.Clear();
}
// Return the encrypted bytes from the memory stream.
return outStr;
}
Thanks.

The equal sign is there because that's part of it being a Base64 encoded string. It's Base64 encoded, because the encryption process results in a byte-array where not all of the items representable as readable text. I suppose you could try to encode as something other than Base64, but using Base32 or something is only going to make the resulting string far longer, and perhaps too long for the URL.

I've solved using the "Catto" user answer for this StackOverflow question: Encrypt and decrypt a string

decrpyt .Net Encrypted string in iOS

I made some AES encryption in c# and works like a charm. Code here:
public string EncryptStringAES(string plainText, string sharedSecret)
{
if (string.IsNullOrEmpty(plainText))
throw new ArgumentNullException("plainText");
if (string.IsNullOrEmpty(sharedSecret))
throw new ArgumentNullException("sharedSecret");
string outStr = null; // Encrypted string to return
RijndaelManaged aesAlg = null; // RijndaelManaged object used to encrypt the data.
try
{
_pkey = sharedSecret;
// generate the key from the shared secret and the salt
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, _salt);
//_key = key.ToString();
// Create a RijndaelManaged object
aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
_key = Encoding.ASCII.GetString(aesAlg.Key);
// Create a decryptor to perform the stream transform.
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
// Create the streams used for encryption.
using (MemoryStream msEncrypt = new MemoryStream())
{
// prepend the IV
msEncrypt.Write(BitConverter.GetBytes(aesAlg.IV.Length), 0, sizeof(int));
msEncrypt.Write(aesAlg.IV, 0, aesAlg.IV.Length);
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
//Write all data to the stream.
swEncrypt.Write(plainText);
}
}
outStr = Convert.ToBase64String(msEncrypt.ToArray());
}
}
finally
{
// Clear the RijndaelManaged object.
if (aesAlg != null)
aesAlg.Clear();
}
// Return the encrypted bytes from the memory stream.
return outStr;
}
/// <summary>
/// Decrypt the given string. Assumes the string was encrypted using
/// EncryptStringAES(), using an identical sharedSecret.
/// </summary>
/// <param name="cipherText">The text to decrypt.</param>
/// <param name="sharedSecret">A password used to generate a key for decryption.</param>
public string DecryptStringAES(string cipherText, string sharedSecret)
{
if (string.IsNullOrEmpty(cipherText))
throw new ArgumentNullException("cipherText");
if (string.IsNullOrEmpty(sharedSecret))
throw new ArgumentNullException("sharedSecret");
// Declare the RijndaelManaged object
// used to decrypt the data.
RijndaelManaged aesAlg = null;
// Declare the string used to hold
// the decrypted text.
string plaintext = null;
try
{
_pkey = sharedSecret;
// generate the key from the shared secret and the salt
Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, _salt);
//_key = key.ToString();
// Create the streams used for decryption.
byte[] bytes = Convert.FromBase64String(cipherText);
using (MemoryStream msDecrypt = new MemoryStream(bytes))
{
// Create a RijndaelManaged object
// with the specified key and IV.
aesAlg = new RijndaelManaged();
aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
_key = Encoding.ASCII.GetString(aesAlg.Key);
// Get the initialization vector from the encrypted stream
aesAlg.IV = ReadByteArray(msDecrypt);
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
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();
}
}
}
finally
{
// Clear the RijndaelManaged object.
if (aesAlg != null)
aesAlg.Clear();
}
return plaintext;
}
NOTE:
I am encryting a fair amout of data here(large json string)
Now the next step would be to make the same magic with iOS here is the problem that I am a newb when it comes to IOS and I am hoping someone can point me in the right direction.
Problems:
I so far failed to find an example on iOS how to make Rfc289 key with secret and salt key
I tryed this example the trick here is that the c# code does not work with large strings it only works with short strings.
Basicly I would like some suggestions or mybe some other aproach to make secure communication between rest api Web Service Application and iOS.
Thank you for help.

Add an SSL certificate to your WebAPI end point - then use fully secure communications endpoint to endpoint, you should not code anything except change http:// to https://

Padding is invalid and cannot be removed Exception while decrypting string using "AesManaged" C#

Please suggest me where i need to update/refactor the code to get rid of exception. I am getting exception while I try to decrypt the encrypted string using following code.
Following line is throwing exception
using (StreamReader srDecrypt = new StreamReader(csDecrypt))
{
// Read the decrypted bytes from the decrypting stream
// and place them in a string.
plaintext = srDecrypt.ReadToEnd();
}
public string EncryptAuthenticationTokenAes(string plainText)
{
byte[] encrypted;
// Create an AesManaged object
// with the specified key and IV.
using (AesManaged aesAlg = new AesManaged())
{
// Create a decrytor to perform the stream transform.
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
aesAlg.Padding = PaddingMode.None;
// 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 the encrypted bytes from the memory stream.
return Convert.ToBase64String(encrypted);
}
public string DecryptPasswordAes(string encryptedString)
{
//Convert cipher text back to byte array
byte[] cipherText = Convert.FromBase64String(encryptedString);
// Declare the string used to hold
// the decrypted text.
string plaintext = null;
// Create an AesManaged object
// with the specified key and IV.
using (AesManaged aesAlg = new AesManaged())
{
// Create a decrytor to perform the stream transform.
ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
aesAlg.Padding = PaddingMode.None;
// 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;
}

Pretty standard bug when using CryptoStream, you forgot to force it to encrypt the last bytes of the stream. It keeps bytes in an internal buffer until enough of them arrive to emit a block. You must force the last few bytes out. Fix:
using (var msEncrypt = new MemoryStream())
using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
using (var swEncrypt = new StreamWriter(csEncrypt)) {
swEncrypt.Write(plainText);
csEncrypt.FlushFinalBlock();
encrypted = msEncrypt.ToArray();
}
You got the exception when decrypting it because encrypted is missing the final padding. The real problem is caused by the using statement, you wouldn't have this problem if you waited obtaining the encrypted bytes until after the CryptoStream is closed. But that doesn't work well because the using statement on the StreamWriter also closes the CryptoStream and the MemoryStream. Explicitly using FlushFinalBlock() is the best workaround.

The input data is not a complete block

Scenario: One symmetric key, each user has his own IV, the documents are stored in a NVARCHAR(MAX) field. When I try to to decrypt the file, I get:
The input data is not a complete block.
// Create symmetric key
public static byte[] CreateKey()
{
AesCryptoServiceProvider aesCrypto = (AesCryptoServiceProvider)AesCryptoServiceProvider.Create();
byte[] key = aesCrypto.Key;
return key;
}
//Get key (stored in a database)
public static Byte[] GetAppKey()
{
return db.Encryptors.Where(x => x.EncryptorID == 1).Single().EncryptionKey.ToArray();
}
// Get application IV (stored in database)
public static Byte[] GetAppIV()
{
return db.Encryptors.Where(x => x.EncryptorID == 1).Single().IV.ToArray();
}
// Encrypt document (this will be stored in a VARBINARY(MAX) field
public static byte[] EncryptBinaryToBytes(Binary document, byte[] iv)
{
byte[] key = GetAppKey();
byte[] encrypted;
using (AesCryptoServiceProvider aesCsp = new AesCryptoServiceProvider())
{
aesCsp.Key = key;
aesCsp.IV = iv;
ICryptoTransform encryptor = aesCsp.CreateEncryptor(aesCsp.Key, aesCsp.IV);
using (MemoryStream msEncrypt = new MemoryStream())
{
using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
{
swEncrypt.Write(document);
}
encrypted = msEncrypt.ToArray();
}
}
}
// return the encrypted document
return encrypted;
}
// Decrypt document
public static byte[] DecryptBytesToBytes(byte[] document, byte[] iv)
{
byte[] key = GetAppKey();
using (AesCryptoServiceProvider aesCsp = new AesCryptoServiceProvider())
{
aesCsp.Key = key;
aesCsp.IV = iv;
ICryptoTransform decryptor = aesCsp.CreateDecryptor(aesCsp.Key, aesCsp.IV);
using (MemoryStream msDecrypt = new MemoryStream())
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Write))
{
using (StreamWriter swDecrypt = new StreamWriter(csDecrypt))
{
swDecrypt.Write(document);
}
byte[] decrypted = msDecrypt.ToArray();
// return the unencrypted document
return decrypted;
}
}
}
}
Thanks in advance.
To store the document
byte[] fileByte = fluUploadFile.FileBytes;
Binary document = new Binary(fileByte);
byte[] appIv = AES.GetAppIV();
byte[] encryptedDocument = AES.EncryptBinaryToBytes(document, appIv);
byte[] decryptedDocument = AES.DecryptBytesToBytes(encryptedDocument, appIv);
Document d = new Document()
{
OriginalName = originalName,
DocSize = fileSize,
BinaryDocument = encryptedDocument,
UploadedName = uploadedFileName,
MimeType = MIMEType,
DocExtension = extension
};
db.Documents.InsertOnSubmit(d);
db.SubmitChanges();

It's really important that you change the data type of the database field to VARBINARY(MAX), that way you avoid issues with character encodings and byte combinations that cannot be interpreted as legal characters.
Also, I think the problem is that you are not closing the streams before calling ToArray() method on the MemoryStream in both encrypt and decrypt routines. It's very important to call Close() in the CryptoStream so that FlushFinalBlock() is called and the encryption process writes the final block to the stream.
Try moving the call to MemoryStream.ToArray() to the outer using block, that is, outside the using block of CryptoStream, so that Dispose() is called on the CryptoStream and call MemoryStream.Close() before that.
Another problem with your code is that you are wrapping the CryptoStream with a StreamWriter, which writes the text representation of the object you pass into the Write method. You should instead write directly to the CryptoStream to avoid any byte to string conversions.