A SECURE PRIVACY PRESERVING DATA AGGREGATION SCHEME BASED ON

BILINEAR ELGAMAL CRYPTOSYSTEM FOR WIRELESS COMMUNICATION

1N. Himaja,

2S. Kolangiammal

1,2Dept. Electronics and Communication Engineering

SRM Institute of Science and Technology, Chennai, India 1nhimaja488@gmail.com, 2kolangiammal.s@ktr.srmuniv.ac.in

Abstract: In the development of communication

system, the data security plays a vital role which

involves more randomization and increases the security provided using various cryptographic algorithms. Now-

a-days network security has become an important

concern. The cryptography techniques are newer and

very efficient that can reduce security threat. In this

paper, we propose the combination of AES, RSA and

Elgamal algorithms which has more randomization in

the secret keys to provide information security system

against various attacks. It shows the secret messages

encryption and decryption process and made

authentication. This design supports multiple security

levels through different key sizes, power, randomization

for data path and key expansion. While the data is

transferring from end- to-end wirelessly, the data is being encrypted and decrypted. If an attacker seeks to

decrypt an intercepted message may try to find the

private key. In such circumstances the seeker needs to

compute the algorithm. No actual method exists for this,

given certain requirements on the initial group are met.

In this case, the data is secure.

Index Terms: Randomization, AES, RSA, Elgamal,

Wireless, Data.

1. Introduction

Cryptography is the most important technology to

protect the data. Modern cryptography has the intersection of mathematical theory and computer

science. The fast development of IoT devices enables

heavy combination of technologies from

communication technology, cloud computing, artificial

intelligence, sensing technology, data processing. IoT

devices transmit data through wireless networks may

contain the private data or the secret data, then this type

of environment includes security issues such as cyber

attacks, personal privacy and organized crimes. To

overcome these problems, it should have some features

such as data encryption, device identification, user

authentication. These functions based on cryptographic

algorithms. They have the importance in terms of cost, energy consumption, throughput, power consumption.

Advanced Encryption Standard(AES) is a symmetric

key encryption standard used to secure data where data

confidentiality is an important and critical issue. This key has high efficiency which is suitable to encrypt a

relatively long plaintext. AES is an asymmetric block

cipher which can encipher and decipher the

information. Encryption means converting data to an

unintelligible form called cipher text. It has 128, 192,

256 bit key lengths. It’s cryptography hardware which

has many applications with less logic

implementations[1]. For the encryption process, the

input state should be XORed with first four words of

the key. The same thing should be done for the cipher

text state array with the last four words in the

decryption process. Rivest - Shamir - Adleman(RSA)

algorithm is vastly used to secure sensitive data. It is used for public-key encryption. Here two keys are

generated. One is public key which is known to all and

the private key which is known only to the end user.

The combination of AES and RSA are used in

communication security with come cryptographic

primitives[2]. Elgamal algorithm is an additional layer

used to secure data which has both symmetric and asymmetric keys. It generates cipher text which is more

complex but it becomes slow when we encrypt and

decrypt it[3]. Compared to the original RSA, the

proposed algorithm requires less computing time.

Elgamal encryption can encrypt more plain text at a

time. It security depends on the hash function which

has the advantage of difficult identification[4]. The hop-by-hop framework is more efficient to provide

privacy between sensors nodes and sink than the end-to-

end one but has a disadvantage of leakage of data to the

adversary[5]. Raspberry Pi is provided to communicate

with different embedded vehicles to achieve

bidirectional data transmission[6]. A remote health

monitoring system based on SPPDA bilinear pairing

scheme which has the advantages of bandwidth

efficiency, data privacy, data aggregation efficiency[7].

2. Proposed Method

The proposed method block diagram is shown below in Fig.1. It consists of a gas sensor, a moisture sensor, an

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LDR, a temperature sensor, an ADC and two Raspberry

Pi modules at two different nodes.

As shown in the block diagram, the data is

collecting from the sensors and giving to the ADC. So

that the ADC converts the analog data to digital data and

transferring the converted data to the Raspberry Pi at

node 1.

Figure 1. Proposed Block Diagram

The data is encrypted at node 1 using hybrid

cryptography consists of AES, RSA and Elgamal

algorithms and generating a private key. This is called

cipher text. Then the data is transmitted via wireless to

node 2. The transmitted data is being encrypted using

the decryption algorithm and converts the ciphertext to

original text.

In this concept we make three levels of security:

• We can change RSA key size for key encryption and

decryption.

• We can manually generate hashing with 256 bit rate.

• We do RSA in 128 bit for data encryption and

decryption.

Figure 2. Encryption and Decryption Process

3. Hardware Requirements

1. Raspberry Pi 3

Raspberry Pi 3 Model B is the newest version of

Raspberry Pi. It is a pocket size card computer. It has a

keyboard, power supply, display, mouse, micro SD card

with installed Linux distribution. It works faster, more

powerful than its predecessors. It support more powerful

external USB devices, 2.5A adapter is recommended. In the latest model, it has in- built wireless and bluetooth

connectivity.

• Broadcom BCM2837 64bit ARMv7 Quad Core

Processor powered Single Board Computer running at

1.2GHz

• BCM43143 WiFi on board

• Bluetooth Low Energy (BLE) on board • 40pin extended GPIO

• 4x USB 2 ports

• Composite video port and 4 pole stereo output

• Uses micro SD port to store data and to operate system

• Full size HDMI

• CSI camera port for connecting the Raspberry Pi

camera

• Micro USB power source upto 2.4 Amps

• Expected to have the same form factor has the Pi 2

Model B, however the LEDs will change position

• Power - Micro USB socket 5V1, 2.5A

• Ethernet - 10/100 baseT ethernet socket

• DSI display port to connect the touch screen display • Video output

-HDMI

-Composite RCA (PAL and NTSC)

• Audio output

- Audio output 3.5mm jack

- HDMI

• USB 4 x USB 2.0 connector

2. Sensors

A sensor is a module, an electronic component. Its

purpose is to detect changes in the environment and send

information to a computer processor. Sensor data maybe

the input of the another system and it is in the integral component of the increasing reality of IoT. Here a few

sensors are used in this project.

A. Gas sensor (MQ2)

B. Humidity sensor

C. LDR

D. Temperature sensor (LM35)

A. Gas sensor

The leakage of gas in home and industry can be detect

using MQ-2 gas sensor. These sensors are used indoors

at room temperature and are sensitive to range of gas. Its

output is an analog signal. Due to its high sensitivity, response is fast and measurements can be taken as early

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as possible. By the potentiometer, the sensitivity can be

adjusted.

Benefits: • Long life stable

• Wide detecting scope

• Simple drive circuit

• Fast response and high sensitivity

B. Humidity Sensor

Humidity sensor is used in measuring environmental hu-

midity. It is also called as Hygrometer. Based on the

type of humidity, these sensors are classified and used

for measuring. Here this sensor is based on Resistive

effect. Resistive type humidity sensor respond to the

change in the humidity, pickup changes in the resistance

value of the sensor.

C. LDR

Light Dependant Resistor (LDR) is a resistor which is

also called photo conductor, photo resistor, photocell. It

is a special type of resistor in which resistance value

depends on the amount of light falling on the surface. A

typical LDR has resistance of 1MOhm in the presence

of darkness, a couple of KOhm resistance in the

brightness. LDR depends on the light. When light falls

on its surface, the resistance will decrease and in the

absence of light, the resistance will increase.

• Peak wavelength - 600nm • Max voltage @ 0 lux - 200v

• Peak power dissipation - 200mW

D. Temperature sensor

LM35 is the precision type temperature sensor,

temperature can be measured accurately compared to the thermistor. Its operating temperature ranges from -

55°C to 150°C. It posses low self heating with limit of

0.1°C, linear output, low output impedance. It has

analog output with 30v capability and many

applications on battery management, power supplies

etc.,

Features: • Suitable for remote applications

• Operates from 4v to 30v

• Calibrated directly in celsius

• Low cost due to wafer-level trimming

3. ADC(MCP3008)

It is a 10-bit analog to digital converter(ADC) with 8

channels at low cost. It is similar to Arduino Uno in the

case of ADC and read a few analog signals from Pi. It

connects to Raspberry Pi in SPI connection. It uses

hardware SPI bus, software SPI to talk to the MCP3008,

any 4 GPIO pins.

E. Serial Peripheral Interface Communication

It is a communication bus which interfaces one or more

slave peripheral IC’s to a single master SPI device.

Each SPI peripheral IC has analog to digital converter, GPIO pins, accelerometer, temperature sensing IC,

digital to analog converter and so on. In this way SPI

bus and I2C bus are similar. The advantage of SPI bus

is very high as the hardware than the I2C bus. The I2C

bus is a 2-wire bus used to connect upto 127 devices

and more depending on the 9-bit addressing scheme is

used in the place of 7-bit address. The SPI bus has one master device and more than 3 slave devices. SPI bus

requires 6 wires corresponding to the 6 pins to interface

3 slave SPI devices to the master SPI controller required

on the master SPI device. The 3 wires shared by all

devices on the SPI bus are:

1. Master out slave in (MOSI) - Data is moved from

master to slave in this wire.

2. Master in slave out (MISO) - Data is moved from

slave to master in this wire.

3. Serial clock (SCLK) - It is used to synchronize the

transmission of data between devices on the bus

generated by the master controller.

With these additionally the bus has ’n’ wires for ’n’ slave devices. Each wire carries chip select

signal(CS or SS) for its respective device. At a time,

only one slave device can own its chip select signal

asserted by the master controller at a time.

4. Software Results

The RSA algorithm is used to generate private key and

public key for the data. Then these keys are called in

AES algorithm to encrypt the keys. At node 1, from

Raspberry Pi the encrypted key is passed to the

Raspberry Pi 3 at node 2. The Elgamal algorithm

provides an additional layer of security the Elgamal

algorithm, the key will be decrypted and get the original data at node 2.

1) The private key and public key are generated for the

text using RSA algorithm is Fig.3.

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Figure 3. Private and Public key generation

2) The encrypted data with encryption time is shown in Fig.4.

Figure 4. Encrypted data

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3) The decrypted/original data with decryption time is shown in Fig.5.

Figure 5. Decrypted data

5. Hardware Results

The connections of hardware are made as shown in

Fig.6. The voltage power supply can be 3.3V. ADC

MCP3008 communicates with Raspberry pi 3 in a SPI

communication. Then interface the Raspberry pi 3

module and a system with a common IP address. Run

the sensors program that is already dumped in the memory card and get the sensors output values.

Figure 6. Hardware Kit

4) The Fig.7 shows measuring the accurate values of

gas sensor, LDR, humidity sensor and temperature

sensor.

Figure 7. Sensors Output

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6. Conclusion and Future Enhancement

In this paper, RSA algorithm is combined with the AES

and Elgamal algorithms. Using RSA algorithm, the

public key and private key are generated. These keys

are then passed to the AES. The AES algorithm will

give the encrypt key and calculates the encryption time.

At node 2, the same algorithm using decryption key will

give decrypted/original data. A few modifications are

also done in this process; which leads to an increased efficiency of our system. The encryption time and

throughput of AES is improved than the RSA. Elgamal

is combined with AES-RSA to provide additional layer

for more secure as it has both symmetric and

asymmetric keys. Finally, the encryption time and

throughput of the proposed system will give better

result than the existing system. In the future work, this hybrid cryptography is

used for the generation of digital signature to send

multiple messages at a time, cloud computing, health

monitoring applications in order to ensure end user

security.

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