IV.SECUTIRY TECHNIQUES

In the present era various number of

applications are relying on internet such online shopping , stock trading,

internet banking, digital bill payment etc., All these public networks need to

have the end to end connection in a

secured manner which should also be confidential in order to ensure data

authentication, confidentiality ,availability

integrity as well as accountability.

As per NIST computer security can be defined as the

protection afforded to an automated information system in order to attain the

applicable objectives of preserving the integrity ,availability of

confidentiality of information system resources(inclusion hardware, software,

firmware ,data /information and tele-communications)

Security is the process of protecting

the services and information from an unauthorised access, modification or

distruction . In networking the security can be obtained by using cryptography (one

of science and art) is of

transforming the messages so that

they can be protected by attacks.

Encryption is one of important mechanism which can ensure the security of sensitive

information. The encryption algorithms

are classified into two groups: symmetric key(secret key) and asymmetric

key(public key)579

Symmetric key: it is also known as conventional encryption is a form of cryptosystem

in which encryption and decryption performed using same key57 9

Asymmetric encryption : In which encryption and decryption

are performed using the different keys

ie., public key, private key.5 9

V.EXISTING ALGORITHMS FOR SECURITY

In

data communication encryption plays a major role to secure the data. The

encryption algorithms714 used in cloud computing are

1.Symmetric encryption algorithms:

In this method sender and

receiver use a single secret key which is used to encrypt and decrypt the

messages. Some of the encryption algorithms are

a)

DES(Data

Encrytpion Standard): It is a symmetric key algorithm used to encrypt

the information. It was developed by IBM in 1975. In DES algorithm block cipher

is of 64bits and key is of 56bits. Now a days this algorithm is insecure for

lots of applications.514

b)

3DES(Tripple

Data Encryption algorithm): It is developed to overcome the flaws of DES

without designing a new crypto system. It

was developed by IBM in 1978. 3DES extends the key size of DES by applying the

algorithm 3 times in succession with 3 different keys. The combined key size is

thus 168 bits( 3times to DES(3*56)).TDEA uses three 64bit keys K1,K2,K3 in

Encrypt-Decrypt-Encrypt(EDE) mode. 3DES is slower than other block cipher

methods.514

c)

AES(Advanced

Encyrption Standard): Is one of the new encryption standard recommended

by NIST to replace DES in 2001. AES can support any combination of data

(128bits ) and key length of 128,192 and 256 bits. During encryption and

decryption process AES goes through 10 rounds for 128 bit keys, 12 rounds for

192 bit keys and 14 rounds for 256 bit keys to deliver final cipher text. The

draw back of this algorithm is difficult to implement.57

d)

BlowFish:

Is

a symmetric key algorithm designed by Bruce Schneier in the year 1993. It is a

basic algorithm developed an option to DES algorithm to overcome many problems that come with many

other algorithms. This algorithm is available in public domain. And can be

available to free to every one.7.The key size is 32-448 bits and 16 rounds.

e)

RC5(Rivest

Cipher): Is a symmetric key algorithm.

Mainly known for its simple execution. This is developed by Ronald Rivest in

1994. The speed of algorithm is slow comparative to other algorithms

2.Asymmetric Algorithms:

These are public key algorithms which generally

make use of different keys for encryption and decryption. These algorithms are

most important because these can be used for transmission of encryption keys.

a) RSA

(Rivest-Shamir-Adeleman): Is the most simple and common asymmetric

algorithm used for both encryption and decryption of digital signature. It has

fast encryption key.514. . It was developed by Ronrivest,Adi shamir,and

Leonard Adleman in 1978.

b) DSA : It is an important algorithm for

processing the digital data. It was given by the NIST in the year august 1991.

c) Diffie-Hellman : Is the earlier

asymmetric data standard algorithm developed in the year 1976. This algorithm

most widely used key exchange algorithm14

VI.CONCLUSION

Cloud computing provides an enormous benefits of cloud services and

resources in various fields. However cloud security issues remain the major

obstacles that may prohibit the adoption

of cloud computing on a large scale. Security

engineering is one of the best practices to provide the best methods and

techniques for developing systems and services which are built for security, sustainability

and resiliency. In this paper the overview of various security threats, attacks with solutions, security

issues , challenges , risks and some of the encryption techniques were

discussed.