Below is my code that attempt to encrypt the data

input/invoke my encryption method:

```
[self myED:@"wcc123" :@"hahaha" :@"yyyy"];

- (NSData*) myED:(NSData*)data :(NSData*) key :(NSData*)iv{

    @try {
        // Try something
        NSLog( @"Original String: %@", data );

        size_t bufferSize = [data length]*2;
        void *buffer = malloc(bufferSize);
        size_t encryptedSize = 0;    
        CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,                                          
                                              [key bytes], [key length], [iv bytes], [data bytes], [data length],                                          
                                              buffer, bufferSize, &encryptedSize);  
    }
    @catch (NSException * e) {
        NSLog(@"Exception: %@", e); 
    }
    @finally {
        // Added to show finally works as well
    }

    return nil;

}

```

However, when try to run this code and it prompt me exception below 

> 
> 2012-07-03 16:52:44.776 wccTest[930:f803] Exception:
>  -[\_\_NSCFConstantString bytes]:
> 
> 
> 

Can anyone help/advice on this?