No abstract

Recent growth in the development of e-commerce and cloud Computing, SSL protocol is more and more widely deployed security protocol used in all kinds of network services. SSL protocol by providing end to end secure authentication, message encryption, data integrity check and other security mechanisms protects the security of the communication process over a computer network. In recent years, due to the development of cloud computing, the reliable connection security between the client and the cloud is also an extremely important issue. SSL have total three sub protocols under it: Handshake Protocol; Record Protocol and Alert Protocol. Handshake protocol defines how to establish the secure connection between the client and the server using the cipher suites and other parameters that both have agreed upon. Record Protocol defines how to encrypt the data that is to be sent through the network using the key that have been established during the handshake protocol. Alert protocol defines how to send the custom messages to other whenever they detect any intrusion in the system. The goal of our proposed system is to create secure channels over insecure networks using Diffie Hellman key agreement protocol.

This paper presents algorithms for encryption and decryption developed using pseudo random number generator (PRNG) and non-Linear functions. PRNG used in the work are matlab random number generator (RNG) and Linear congruential generator (LCG). The developed algorithms are named according to PRNG used in it. State of PRNG is considered as secret key of the cipher. The encryption schemes have been cryptanalyzed for four different methods to test its strength like key space analysis, plaintext and key sensitive test. Known plaintext attack is also performed by taking into consideration a small string of plaintext and the complete cipher text for small text. The analysis is performed on different keys selected randomly from key space for various texts and files.Key sensitivity up to 50 % and plaintext sensitivity ranging from 3% to 50 % have been obtained in the developed ciphers. It is concluded that proposed encryption algorithms have strength against linear, differential and statistical attacks.

The proposed hybrid message embedded scheme consists of hill cipher combined with message embedded chaotic scheme. Message-embedded scheme using non-linear feedback shift register as non-linear function and 1-D logistic map as chaotic map is modified, analyzed and tested for avalanche property and strength against known plaintext attack and brute-force attack. Parameter of logistic map acts as a secret key. As we know that the minimum key space to resist brute-force attack is 2100, and it is observed from analysis that key space of the discussed method is lesser than 2100. But the identifiability test concludes that the scheme consists of identifiable keys which are sufficient condition to resist brute-force attack for chaotic ciphers.A complete file can be encrypted and decrypted successfully by the method that assures security against brute force attack. It is also concluded that the scheme has an average key sensitivity. KEYWORDSHybrid message embedded scheme, Non-Linear Shift Register, Logistic map, Brute-force attack.

This paper proposes three different chaotic encryption methods using 1-D chaotic map known as Logistic map named as Logistic, NLFSR and Modified NLFSR according to the name of chaotic map and non-linear function involved in the scheme. The designed schemes have been crypt analyzed for five different methods for testing its strength. Cryptanalysis has been performed for various texts using various keys selected from domain of key space. Logistic and NLFSR methods are found to resist known plaintext attack for available first two characters of plaintext. Plaintext sensitivity of both methods is within small range along with medium key sensitivity. Identifiability for keys of first two of the scheme has not been derived concluding that methods may prove to be weak against brute-force attack. In the last modified scheme avalanche effect found to be improved compared to the previous ones and method is found to resist brute-force attack as it derives the conclusion for identifiability