(Objective-C) AES Encryption ECB Mode with PKCS7 Padding

Duplicates the following C# code:

public static byte[] DecryptBySymmetricKey(string encryptedText, byte[] key)
  {
     string keyAsBase64 = Convert.ToBase64String(key);

     byte[] dataToDecrypt = Convert.FromBase64String(encryptedText);
     var keyBytes = key;
     AesManaged tdes = new AesManaged();
     tdes.KeySize = 256;
     tdes.BlockSize = 128;
     tdes.Key = keyBytes;
     tdes.Mode = CipherMode.ECB;
     tdes.Padding = PaddingMode.PKCS7;
     ICryptoTransform decrypt__1 = tdes.CreateDecryptor();
     byte[] deCipher = decrypt__1.TransformFinalBlock(dataToDecrypt, 0, dataToDecrypt.Length);
     tdes.Clear();
     string EK_result = Convert.ToBase64String(deCipher);
     return EK_result;
}

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

#import <CkoCrypt2.h>
#import <NSString.h>

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

CkoCrypt2 *crypt = [[CkoCrypt2 alloc] init];

// In the C# code above that is to be duplicated here, use the base64 encoded key.
NSString *keyAsBase64 = @"...";
NSString *encryptedBytesAsBase64 = @"....";

crypt.KeyLength = [NSNumber numberWithInt:256];
crypt.CryptAlgorithm = @"AES";
crypt.CipherMode = @"ecb";
crypt.PaddingScheme = [NSNumber numberWithInt:0];
[crypt SetEncodedKey: keyAsBase64 encoding: @"base64"];

crypt.EncodingMode = @"base64";

// Pass the base64 representation of the encrypted data.
// (The EncodingMode indicates you are passing base64.)
NSString *EK_result = [crypt DecryptStringENC: encryptedBytesAsBase64];

NSLog(@"%@",EK_result);