Web service to Xcode encryption - ios

Question

I am trying encrypt data on an iPhone and send up the encrypted text to a web service for them to decrypt it. If the decryption works then it returns the First name in the xml as a confirmation things worked. Here is my Xcode
Note: The 'key' is the same in both xcode and web service
The information I want encrypted:
NSString *fnameencrypted = [[NSString alloc] AES256EncryptWithKey:f_name.text withKey:key]];
NSString *lnameencrypted = [[NSString alloc] AES256EncryptWithKey:l_name.text withKey:key]];
The NSString method
-(NSString *)AES256EncryptWithKey:(NSString *)plaintext withKey:(NSString *)key{
NSData *plainData = [plaintext dataUsingEncoding:NSASCIIStringEncoding];
NSData *encryptedData = [plainData AES256EncryptWithKey:key];
NSString *encryptedString = [encryptedData base64Encoding];
return encryptedString;
}
EDIT
The encryption method
-(NSData *)AES256EncryptWithKey:(NSString *)key{
char keyPtr[kCCKeySizeAES256 + 1]; // room for terminator (unused)
bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
// fetch key data
[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSASCIIStringEncoding];
NSUInteger dataLength = [self length];
//See the doc: For block ciphers, the output size will always be less than or
//equal to the input size plus the size of one block.
//That's why we need to add the size of one block here
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc( bufferSize );
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionECBMode + kCCOptionPKCS7Padding,
keyPtr, kCCKeySizeAES256,
NULL /* initialization vector (optional) */,
[self bytes], dataLength, /* input */
buffer, bufferSize, /* output */
&numBytesEncrypted);
if(cryptStatus == kCCSuccess){
//the returned NSData takes ownership of the buffer and will free it on deallocation
return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
}
free(buffer); //free the buffer
return nil;
}
Here is my web service code
private static string Decrypt(string encryptedText, string completeEncodedKey, int keySize)
{
RijndealManaged aesEncryption = new RijndealManaged();
aesEncryption.KeySize = keySize; //keySize is 256
aesEncryption.BlockSize = 128;
aesEncryption.Mode = CipherMode.ECB;
aesEncryption.Padding = PaddingMode.PKCS7;
aesEncryption.IV = Convert.FromBase64String(ASCIIEncoding.ACSII.GetString(Convert.FromBase64String(completeEncodedString)).Split(',')[0]);
aesEncryption.Key = Convert.FromBase64String(ASCIIEncoding.ACSII.GetString(Convert.FromBase64String(completeEncodedString)).Split(',')[1]);
ICryptoTransform decrypto = aesEncryption.CreateDecryptor();
byte[] encryptedBytes = Convert.FromBase64CharArray(encryptedText.ToCharArray(), 0, encryptedText.Length);
return ASCIIEncoding.ASCII.GetString(decrypto.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length);
}
This code does not work because it returns
<response><return>0</return></response>