This document describes a code modulation based encryption and decryption technique for secure wireless communication. The system has a transmitter section and receiver section, each designed around a microcontroller. At the transmitter, data typed into a PC is encrypted using the microcontroller and transmitted via RF. At the receiver, the encrypted data is received, decoded by the microcontroller, and displayed on the PC. To view the actual data, a password must be entered which decrypts the cipher text into plaintext. The block diagram shows the transmitter components include an encoder, microcontroller, MAX232, and RF transmitter. The receiver components include a decoder, microcontroller, MAX232, and RF receiver.

1. CODE MODULATION BASED ENCRYPTION & DECRYPTION
TECHNIQUE FOR SECURE COMMUNICATION IN
WIRELESS
ABSTRACT
In Today’s Electronic communication take important role. Today’s Communication technology
the chatting system from one Place to another is easy and fast. But security is of some concern,
for that we send the data by the system named as Advanced chatting system using
Microcontroller.
In our project we have two sections, one is transmitter section and another one is Receiver
section. The two sections are designed around a microcontroller as a control unit with all the
devices interfaced to it. The main aim of the project is to transmit the data using wireless
communication by encrypting the data. At the receiver side, the encrypted data is decrypted and
is shown in the PC.
According to this project the person who wants to send the data to a remote place has to type the
data from the PC. The data is received by microcontroller and is sent to RF transmitter after
encrypting it. The RF receiver receives the data decodes it and displays the encrypted data in
PC. If the actual data is to be viewed then a password is to be pressed. Now the cipher text is
converted into plaintext.

2. BLOCK DIAGRAM
TRANSMITTER
POWER SUPPLY
Encoder
MICRO
CONTROLLER
(AT89S52)
MAX232
PC
RF TX
RECIEVER
POWER
SUPPLY
DECODER
MICRO
CONTROLLER
MAX232
(AT89S52)
RF RX
PC