Once the data is converted from analog to digital using my pic i need to encrypt it using X-OR or or can i make the PIC to do it before send it to the UART to transmit
well, after run your ADC, you will have 2 registers that contain your analog data in its digital form. But thats it. It just stores it in the registers. You have to tell it what you want to do with it, whether encrypt, or just send through to the uart.