New Secured Wireless Data Communication Using Cryptography (1)

8/3/2019 New Secured Wireless Data Communication Using Cryptography (1)

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SECURED WIRELESS DATA SECURED WIRELESS DATA

COMMUNICATION USINGCOMMUNICATION USING

CRYPTOGRAPHY CRYPTOGRAPHY



INTRODUCTION:INTRODUCTION:

Data communication is the conveyance of any

kind of information from one space to another.

Although the computers can be interconnected

through a traditional cables, the cost of installingsuch cables is very high.

Also, the use of cables requires theirmaintenance to protect them fromunintentional breaks and loss of signal transfer.



y Data communication is established

between two PC·s using Radio Frequency(RF) wireless technology.

y The wireless communication is secured

in the sense that the data to betransmitted is encrypted using anencryption algorithm.



CryptographyCryptography

y Cryptography is a tool that can be used to keepinformation confidential and to ensure itsintegrity and authenticity.

y All modern cryptographic systems are based onKerckhoff's principle of having a publicly-knownalgorithm and a secret key.

y Many cryptographic algorithms use complex

transformations involving substitutions andpermutations to transform the plaintext intothe ciphertext



y Cryptography involves the process of encryption and decryption.

y It is carried out using algorithms

y Cryptographic algorithms are of two

types:

Symmetric (private)

Asymmetric (public)



Symmetric Cryptographic AlgorithmSymmetric Cryptographic Algorithm

y In this algorithm same secret key is used toencrypt and decrypt information.

y A secret key can be a number, a word or just a

string of random letters.y The disadvantage of this algorithm is that if the

secret key is discovered all messages can bedecrypted.

y There are two types of symmetric algorithms

Stream Algorithms

Block Algorithms



Stream ciphers:Stream ciphers:

y This operates on the basis of a time varyinginformation applied to individual bits of plaintext.

y These are better suited for secure transmissionof data over error prone communication .

Block ciphers:

In this the plain text is divided into large blocks

consisting of fixed number of bits. Succesiveblocks of plain text are encrypted using thesame secret key.



Asymmetric EncryptionAsymmetric Encryption



BLOCK DIAGRAMBLOCK DIAGRAM



OperationOperation

y

Initially the sender one who wants tosend the information sends the data using

serial port of PC.

y Then the data is given to microcontroller

using RS ² 232 cable, and later is given toMAX ² 232 for level conversion.

y Microcontroller performs the task of

encryption at transmitter side and sendsthe encrypted data through i/o port to

RF-transmitter



y Here the algorithm used for encryptionand decryption is RC4.

y RC4 is a stream cipher, symmetric keyalgorithm.

y This algorithm produces a stream of

pseudo-random values. The input stream

is XORed with these values, bit by bit.



y The steps for RC4 encryption algorithm is

as follows:

y Get the data to be encrypted and theselected key.

y Create two string arrays.

y Initiate one array with numbers from 0 to255.

y Fill the other array with the selected key.



y

Fill the other array with the selected key.y Randomize the first array depending on

the array of the key.

y

Randomize the first array within itself togenerate the final key stream.

y XOR the final key stream with the data to

be encrypted to give cipher text.



y Then at receiver side the data encrypted

is given to RF-receiver then that gives thedata to microcontroller through i/o port.

y There microcontroller decrypts the dataand gives that to pc again.



y Here the RF-transceiver works at thefrequency of 433Mhz

y This wireless transmission is applicable to

100 feet distance onlyy This uses ASK modulation process for RF

transmission



PIC Microcontroller Core Features:PIC Microcontroller Core Features:

y High-performance RISC CPU

y Only 35 single word instructions to learn

y All single cycle instructions except for program brancheswhich are two cycle

y Operating speed: DC - 20 MHz clock input DC - 200 nsinstruction cycle

y Up to 8K x 14 words of FLASH Program Memory,

y Up to 368 x 8 bytes of Data Memory (RAM)y Up to 256 x 8 bytes of EEPROM data memory

y Pinout compatible to the PIC16C73B/74B/76/77

y Interrupt capability (up to 14 sources)

y Eight level deep hardware stack

y Direct, indirect and relative addressing modesy Power-on Reset (POR)

y Power-up Timer (PWRT) and Oscillator Start-up Timer(OST)

y Watchdog Timer (WDT) with its own on-chip RC oscillator

for reliable operation



y Programmable code-protection

y Power saving SLEEP mode

y Selectable oscillator options

y Low-power, high-speed CMOS FLASH/EEPROM technology

y Fully static design

y In-Circuit Serial Programming (ICSP) via two pins

y Single 5V In-Circuit Serial Programming capability

y In-Circuit Debugging via two pins

y Processor read/write access to program memory

y Wide operating voltage range: 2.0V to 5.5V

y High Sink/Source Current: 25 mA

y Commercial and Industrial temperature ranges

y

Low-power consumption:y < 2 mA typical @ 5V, 4 MHz

y 20 mA typical @ 3V, 32 k Hz

y < 1 mA typical standby current



Peripheral FeaturesPeripheral Features

y Timer0: 8-bit timer/counter with 8-bit prescaler

y

Timer1: 6-bit timer/counter with prescaler, can beincremented during sleep via external crystal/clock

y Timer2: 8-bit timer/counter with 8-bit period register, pre-scalar and post-scalar

y Two Capture, Compare, PWM modules

y Capture is 6-bit, max. resolution is 12.5 ns

y Compare is 6-bit, max. resolution is 200 ns

y PWM max. resolution is 10-bit

y 10-bit multi-channel Analog-to-Digital converter

y Synchronous Serial Port (SSP) with SPI (Master Mode) andI2C (Master/Slave)

y Universal Synchronous Asynchronous Receiver Transmitter(USART/SCI) with 9-bit address detection

y Parallel Slave Port (PSP) 8-bits wide, with external RD, WRand CS controls (40/44-pin only)



Pin layout of PIC16F877APin layout of PIC16F877A



Architecture of PIC 16F877AArchitecture of PIC 16F877A



Advantages:Advantages:

y Information can be transmitted securelywith in a limited range.

y Simple to implement.

Disadvantages:

It is applicable only to shorter distances.



ConclusionConclusion

y Thus the information can be transmittedsecurely using this project.

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New Secured Wireless Data Communication Using Cryptography (1)