code: function lockCrc(inputStr){
  
  		res = 0xff;
  		inputHex = new Buffer(inputStr,'hex');
  
  		//start from the second byte 
  		for (i = 1; i<= inputHex.length; i++) {
  			res = res ^ inputHex[i];
  		}
  		//add padding
  		reshex = (res+0x100).toString(16).substr(-2);
  //		console.log(reshex);
  
  		return(inputStr+reshex);
  }
docs: returns string with calculated CRC attached