DOI 10.4010/2016.1159 ISSN 2321 3361 © 2016 IJESC Research Article Volume 6 Issue No. 5 Secure Data Retrieval in Ad-Hoc Network using RC6 Algorithm Shubhangi More1, Pallavi Shinde2, Sabiya Shaikh3, Vipul Gunjal4, Sushil Chavan5, Aditi Kalia6, Vaishali Kolhe7 Department of Computer Engineering DYPCOE, Akurdi, SPPU, Maharashtra, India [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected] Abstract: Cryptography is an important for secure data transmission. Encrypted data is more secure to transmit over insecure network and any unauthorized user won't be able to read the encrypted data if he don’t have the secret key to decrypt the message. The ad-hoc network provides a scenario for authorization policies and the secure data retrieval in most challenging cases. Various encryption techniques have been proposed for data and network security. RC6 algorithm is used in the proposed system for encryption and decryption. The security level depends upon encryption key size and the complexity of encryption algorithm. RC6 can support a wide variety of word-lengths, key sizes and number of rounds thus increases the efficiency. Keywords: RC6 cryptography, ABE, cipher, multiple authority, Secure data retrieval, Decentralized network. I. Introduction RC5 include using four w-bit word registers, integer Secure communication can be done through multiplication as an additional primitive operation, and insecure channels by using cryptography. Only the data introducing a quadratic equation into the transformation. from alterations and theft is not protected by this, but also provides user authentication. Plaintext is original data. II. Literature survey Encrypted plain text is called as cipher text. When cipher Encrypting data provides additional benefits text is decrypted we will again get the original plain text. besides protecting the confidentiality of a message. These Cipher text-policy ABE (CP-ABE) provides a advantages ensuring that messages have not been altered adaptable way of encrypting data such that the encryptor during transit and verifying the identity of the sender. There defines the attribute set that the decryptor should possess in are various types of cryptography techniques. order to decrypt the cipher text. Thus, different users are allowed to decrypt different pieces of data as per the 2.1 Asymmetric Key Cryptography security policy. In CP-ABE, the key authority generates The keys used for encryption and decryption are private keys of users by applying the multiple authority’s different but purpose is same. This technique is also known master secret keys to users’ defined set of attributes. Thus, as Public Key Cryptography. The data is encrypted using a the multiple key authority can decrypt cipher text addressed public key whereas the decryption can be done only by the to specific users by generating their attribute keys. If the key private key. Public Key Cryptography depends upon authority is compromised by attackers when deployed in the mathematical functions/one-way functions, which are easy hostile environments, this could be a potential threat to the to compute but it is difficult to compute their inverse data confidentiality or privacy when the data is highly function. sensitive. ABE is a public key encryption type in which user’s secret key and the cipher text both are indirectly 2.2 Cryptography Using Hash Function dependent on the attributes. This is mainly used for log In order to transform a large block of a string of encryption. ABE is a promising approach that fulfills the data to a small block of data A cryptographic hash function requirements for secure data retrieval. ABE suggests a is used. This is a one way function so, it means that the mechanism that enables an access control over encrypted transformation is done in a way so that recreation of that data using access policies and described attributes. The original data is difficult or say impractical. Further, it is also problem of applying the ABE is several security and privacy difficult to find two strings which may be transformed to the challenge. Since some users may change their correlated same hash. RC algorithms belong to a family of symmetric- attributes at some point (for example, moving their region), key encryption algorithms. They were first invented by Ron or some private keys might be compromised, key update for Rivest. “RC” stands for Rivest Cipher. The RC algorithms each attribute is necessary in order to make systems secure. are widely deployed in many networking applications RC6 algorithm is used to encrypt and decrypt the message because of their favourable speed and variable key-length which will be stored on storage node. When a person sends capabilities. message to another person in ad-hoc network that message will be encrypted and it will be stored at the storage node 2.3 Symmetric Key Cryptography and the message will be retrieved by the receiver by The same keys are used for encryption and for decrypting it using same algorithm. Improvements over decryption. The secret key should be known to both the International Journal of Engineering Science and Computing, May 2016 4657 http://ijesc.org/ sender as well as the receiver. Distribution of the key is the 32/64/128-bit block cipher designed by Ronald Rivest for difficulty in thiscredentials, and a multiple key authority RSA Data Security (now RSA Security) in December of encrypting data determines a policy for who can decrypt. 1994. It is fast and also provides security if suitable approach. It is generally categorized as being either stream parameters are chosen. The key used is strong if it is long ciphers or block ciphers. Stream ciphers operate on a single and if the key size is short, then the algorithm is weak. bit (byte or computer word) at a time. A block cipher encrypts one block of data at a time. It can be Electronic 2.3.6 RC6 Code Book mode (ECB), Cipher Block Chaining mode RC6 is a block cipher which uses 128 bit block size (CBC), Output Feedback mode (OFB). and supports key sizes of 128, 192 and 256 bits. It was designed in order to meet the requirements of the AES. It is Rivest Cipher Algorithms an improvement of the RC5 Algorithm. RC6 algorithm was Various algorithms which fall under this category a new block cipher submitted to NIST for consideration as are Cipher Feedback mode (CFB), Counter mode (CTR), the new Advanced Encryption Standard (AES) [6,7,8]. The Galois Counter Mode (GCM) and algorithms which fall design of RC6 began with a consideration of RC5 as a under the category of Symmetric key cryptography are: potential candidate for an [9] AES submission. RC1, RC2, RC4, RC5, RC6, AES, DES, 3DES, CAST5. Modifications were then made to meet the AES requirements, to increase security, and to improve 2.3.1 RC1 performance [10, 11]. The inner loop however, is based RC1 was the first step which Rivest took in order to around the same ‘half-round’ found in RC5 [12]. It provides proceed with designing a series of symmetric key even better security against attacks which may be possible algorithms popularly known as the Rivest Cipher in the RC5 Algorithm. It makes use of 4 registers (Each one Algorithms. The main idea of research was to design a of 32 bit) and is more secure than the RC5. It is also Symmetric Key encryption algorithm that could be used by protected from various other possible security attacks. It the users to protect their data as it passes through the uses fewer rounds and offers a higher throughput. network [12]. III. Proposed system 2.3.2 RC2 System architecture: RC2 is a block encryption algorithm, developed in System Architecture as shown in fig. 1 describes the 1987. It was considered as a proposal for the DES working of system. User wants to access the data stored on replacement. It is a secret key block encryption algorithm storage node. If a user possesses a set of attributes satisfying which uses a variable size key from 1 byte to 128 bytes and the access policy of the encrypted data defined by the sender consists of input and output block size of 64-bit each. This then user can decrypt the cipher text and retrieve the data. algorithm was designed to be easily implemented on 16-bit storage node is an entity that stores data from senders and microprocessors [10]. The algorithm itself involves 3 further provide alike access to users. Keys are stored at storage sub algorithms viz. Key Expansion, Encryption, and node. A sender is responsible for defining (attribute-based) Decryption, replacing the existing DES Algorithm. access policy and enforcing it on its own data by encrypting the data under the policy before storing it on the storage 2.3.3 RC3 node. The receiver requests the decryption key to multiple The RC3 algorithm was being developed at RSA key authorities. Multiple key authorities provide encryption security; it was broken at the same time [7]. Hence, it was as well as decryption keys. not used. 2.3.4 RC4 RC4 is a stream cipher designed in 1987 by Ron Rivest for RSA data Security (now RSA Security) [1, 2]. It is a variable key-size stream cipher with byte-oriented operations. This algorithm is used for random permutation. RC4 is used in the Secure Sockets Layer/Transport Layer Security (SSL/TLS) standards that have been defined for communication between Web browsers and servers [3]. RC4 is a stream cipher, symmetric key encryption algorithm. Due to its simplicity it is popular, often used in file encryption products and secures communication, such as within SSL. For confidentiality WEP (Wireless Equivalent Privacy) Fig 1.