title: How to get key used for MD5 algorithm in iPhone/iPad
body: <p>I am using MD5 algorithm for sync with server where I want to send data using MD5 algorithm.
  I wrote following code-</p>
  
  <pre><code>NSString *string =  @"ABC";
      unsigned char *inStrg = (unsigned char*)[[string dataUsingEncoding:NSASCIIStringEncoding] bytes];
      unsigned long lngth = [string length];
      unsigned char result[MD5_DIGEST_LENGTH];
      NSMutableString *outStrg = [NSMutableString string];
  
      MD5(inStrg, lngth, result);
  
      unsigned int i;
      for (i = 0; i &lt; MD5_DIGEST_LENGTH; i++)
      {
          [outStrg appendFormat:@"%02x", result[i]];
      }
      md5TextField.text = outStrg;
  </code></pre>
  
  <p>For decryption at server end I need its key through which MD5 text has been generated.
  What will be its key?
  Thanks in advance...</p>