International Journal of Innovations & Advancement in Computer Science IJIACS ISSN 2347 – 8616 Volume 4, Special Issue May 2015 Comparative Analysis on Different Parameters of Encryption Algorithms for Information Security Shailja Kumari,Jyoti Chawla Department Of Computer Science And Applications Chaudhary Devi Lal University,Sirsa ABSTRACT: If the confidentiality of the information is of very high value, it should be protected. If you want to stop the unauthorized disclosure or alteration of the information, secure it. Cryptography is an area of computer science which is developed to provide security for the senders and receivers to transmit and receive confidential data through an insecure channel by a means of process called Encryption/ Decryption. Encryption algorithms play a main role in information security systems. On the other side, those algorithms consume a significant amount of computing resources such as CPU time, memory, and battery power. This paper presents a comparative analysis on different parameters of encryption algorithms(AES,RC6,IDEA,BLOWFISH) such as Architecture, Flexibility, Reliability, Security and Limitation for information security that are essential for secure communication. General Terms: Algorithms, Encryption, Public Key, Private Key, Architecture, Flexibility, Overview, Limitations, Security. Index Terms—Cryptography, International Data Encryption Standard, Advance Encryption Standard, RC6 , Blowfish. 1. INTRODUCTION Cryptography is basically the process of hiding information. Our ATM cards, computer passwords and transferring data from one place to another are done with cryptography. Data cryptography mainly is the scrambling of the content of data, such as text, image, audio, video and so forth to make the data unreadable, invisible or unintelligible during transmission or storage called Encryption. The reverse of data encryption is data Decryption. Original data that to be transmitted or stored is called plaintext, the one that can be readable and understandable either by a person or by a computer. Whereas the data, which is unreadable, neither human nor machine is called cipher text. Encryption is the process of converting plain text "unhidden" to a cryptic text "hidden" to secure it against data thieves.Cryptography is an area of computer science which is developed to provide security for the senders and receivers to transmit and receive confidential data through an insecure channel by a means of process called Encryption/ Decryption. There are basically three techniques of cryptography- Symmetric, Asymmetric and Hash Function. Fig.1 shows the simple flow of commonly used encryption algorithms. Fig.1 Encryption-Decryption Flow In symmetric encryption, the sender and the receiver agree on a secret (shared) key. Then they use this secret key to encrypt and decrypt their sent messages. Fig.2 shows the process of symmetric cryptography. Node A and B first agree on the encryption technique to be used in encryption and decryption of communicated data. Then they agree on the secret key that both of them will use in this 123 Shailja Kumari, Jyoti Chawla International Journal of Innovations & Advancement in Computer Science IJIACS ISSN 2347 – 8616 Volume 4, Special Issue May 2015 connection. After the encryption setup finishes, node A starts sending its data encrypted with the shared key, on the other side node B uses the same key to decrypt the encrypted messages. Fig.2 Symmetric Encryption 2. OBJECTIVES In this research work, steps involved in our research paper for selecting the algorithm for symmetric encryption are: Select different symmetric encryption techniques. Select the criteria/aspects according to which the best algorithm is to be selected among different symmetric encryption algorithms. Survey the different algorithm characteristics for these selected criteria. Evaluate various algorithms by comparing them to one another with respect to four factors: 1. Architecture 2. Security 3. Flexibility 4. Limitation(Known Attacks) Select the best algorithm of highest priority. 3. LITERATURE REVIEW Literature Review is the selection of available documents on the topic which contain information, ideas ,data and evidence written from a particular standpoint to fulfill certain aims or express certain views on nature of the topic and how it is to be investigated and the effective evaluation of these documents in relation to research being proposed. It seeks to describe, summarize, evaluate, clarify and integrate the content of primary reports. Kofahi (2003) presents an implementation of three encryption algorithms and a comparison between them based on CPU execution time. The CPU execution time is broken down to kernel and user time. The selected algorithms are: DES, Triple-DES (T-DES) and Blowfish. The objective is to evaluate the performance of the three cryptography algorithms in terms of the processing time required in the kernel and user space for generating the secret key, encryption and decryption operations. The results show that the Blowfish algorithm is the fastest, followed by the DES algorithm then the T-DES algorithm [11]. Nadeem,A.(2005) have implemented four of the popular secret key encryption algorithms, i.e., DES, 3DES, AES (Rijndael), and the Blowfish and their performance is compared by encrypting input files of varying contents and sizes, on different Hardware platforms.The performance results have been summarized and a conclusion has been presented. Based on the experiments, it has been concluded that the Blowfish is the best performing algorithm among the algorithms chosen for implementation [12]. Hasib,A.(2008) presents the fundamental mathematics behind the AES and RSA algorithm along with a brief description of some cryptographic primitives that are commonly used in the field of communication security [13]. 124 Shailja Kumari, Jyoti Chawla International Journal of Innovations & Advancement in Computer Science IJIACS ISSN 2347 – 8616 Volume 4, Special Issue May 2015 AL.Jeeva (2012) provides a fair performance comparison between the various cryptography algorithms such as the AES, RSA, RC2, DES, 3DES, DSA where both types of symmetric and asymmetric techniques. We have compared these parameters for both the symmetric key encryption and for the asymmetric key encryption. The parameters such as the tunability,key length, computational speed, and the type of attacks on the security issues are provided. As a result, the better solution to the symmetric key encryption and for the asymmetric key encryption is provided [14]. Dr.Kanak Saxena (2013) focus on dual approach of compression and security where compression is achieved through lossless algorithm (either Huffman coding or LZW) according to size and type of image data and compressed data is encrypted using traditional DES Algorithm. 4.CRITERIA ON WHICH DIFFERENT ALGORITHMS ARE BEING ANALYZED: 4.1 Architecture Defines the structure and operations that an algorithm can perform, its characteristics and how they are implemented. It also determines that the algorithm is symmetric or asymmetric that is whether it makes use of secret key or public key for encryption and decryption. 4.2 Security An affirmative measure of the system strength in resisting an attack is a desirable element of any encryption algorithm possesses the poperty of in distinguishability (built by combining substitution with transposition repeatedly). Security of an encryption algorithm depends on the key size used to execute the encryption: generally, greater the keys size stronger the encryption. Length of key is measured in bits. 4.3 Flexibility Defines whether the algorithm is able to endure minor modifications according to the requirements. 4.4 Limitations (Known Attacks) Defines how fine the algorithm works by make use of the computer resources available to it. Further how often is vulnerable to different types of att 5. ALGORITHM REVIEW 5.1 Overview 5.1.1 Blowfish Blowfish by Bruce Schneier, author of Applied Cryptography, is considered as a highly rated encryption algorithm in terms of security, with different structure and functionality than the other mentioned encryption algorithms. Blowfish is a fast, compact, and simple block encryption algorithm with variable length key allowing a tradeoff between speed and security. Blowfish is a public domain algorithm (unpatented) and is used in the SSL and other program [5]. 5.1.2 IDEA James L. Massey and Xuejia Lai (Zurich, Switzerland) in 1990 developed an encryption algorithm named as International Data Encryption Algorithm (IDEA). It is fairly fast, considered secure, and is also resistant to both linear and differential analysis. 5.1.3 AES AES developed by Joan Daemen and Vincent Rijmen, becomes U.S.'s new Advanced Encryption Standard in October 2000 declared by the National Institute of Standards and Technology. Rijndael using variable key size is extremely fast and compact cipher. Its symmetric and parallel structure provides great flexibility for implementers, with effective resistance against cryptanalytic attacks [18]. AES can be well adapted to a wide range of modern processors such as Pentium, RISC and parallel processors. 125 Shailja Kumari, Jyoti Chawla International Journal of Innovations & Advancement in Computer Science IJIACS ISSN 2347 – 8616 Volume 4, Special Issue May 2015 5.1.4 RC6 RC6 a derivative of RC5, designed by Ron Rivest, Matt Robshaw, Ray Sidney, and Yiqun Lisa Yin [20] is a symmetric key algorithm. It was design to congregate the requirements of the Advanced Encryption