The design of cryptographically secure pseudorandom number generator (CSPRNG) producing unpredictable pseudorandom sequences robustly and credibly has been a nontrivial task. Almost all the chaos-based CSPRNG design approaches invariably depend only on statistical analysis. Such schemes designed to be secure are being proven to be predictable and insecure day by day. This paper proposes a design and instantiation approach to chaos-based CSPRNG using proven generic constructions of modern cryptography. The proposed design approach with proper instantiation of such generic constructions eventually results in providing best of both worlds that is the provable security guarantees of modern cryptography and passing of necessary statistical tests as that of chaos-based schemes. Also, we introduce a new coupled map lattice based on logistic-sine map for the construction of CSPRNG. The proposed pseudorandom number generator is proven using rigorous security analysis as that of modern cryptography and tested using the standard statistical testing suites. It is observed that the generated sequences pass all stringent statistical tests such as NIST, Dieharder, ENT, and TestU01 randomness test suites.

Multicast communication allows a single message packet to be routed to multiple nodes simultaneously. Membership in a multicast group is dynamic, allowing nodes to enter and leave the multicast session. Besides the benefits, multicast communication presents the challenge of securing the communication. In order to preserve confidentiality the general encryption mechanism used for point to point communications are used. A specific encryption mechanism rather a general one is needed to suit the multicast communication requirements wherein the life time of a secret key is very short and requires a frequent change. Moreover, the next generation wireless networks have very limited resources and need a light weight security mechanism. The proposed cipher, Multicrypt, is similar to the One Time Pad and Hill cipher based on a sub band coding scheme using the principle of Orthogonal Vectors. The proposed cipher is based on the assumption of Computational Diffie Hellman problem and insolvability of Hadamard conjecture. It is designed to have multiple keys to decrypt the message like asymmetric cryptosystem so that a (key) compromise of a member would not lead to compromise of the entire system, less computational and communicational overheads, less storage complexity and there is no need for state-full members. This study also presents an extensive security analysis and the performance analysis with RSA, a public key encryption mechanism used to establish session keys. With the help of security analysis the study proves that brute force attack does not compromise the system. Multicrypt cryptosystem has the capability of dynamically adding and revoking members. The performance of Multicrypt is relatively better in terms of key setup time, encryption time, decryption time, encryption throughput and decryption throughput than RSA in the simulated setup. The proposed cipher is also proved to be secure against IND-CPA and IND-CCA attacks