A bitcoin node needs to download the full block contents of the entire blockchain, before actually being able to send and receive transactions on bitcoin broadcast network, except simple payment verification clients which require only block headers and bloom filters to sync with others peers available on the network. Transactions/Blocks pass through a complex process at sender and receiver than it apparently looks to be. During transmission transactions/blocks are broken down into smaller chunks of data so that they can be carried on the wire. These chunks are given appropriate headers, encapsulated and then passed through several layers to reach the destination. In this paper we captured Bitcoin packets using Wireshark and deeply investigated and analyzed them. We investigated how bitcoin transaction/block messages work and what values and parameters are considered during this whole process.

In this paper, we propose a secure, lightweight acoustic pseudo-random number generator (SLA-LFSR-PRNG) that consumes less memory, CPU capacity and adopts the multi-thread parallelization to generate huge random numbers per second by taking the advantages of multi-core CPU and massively parallel architecture of GPU. The generator is based on cryptographically secure Linear Feedback Shift Register(LFSR) and extracts the entropy from sound sources. The major attraction of proposed Pseudo Random Number Generator(PRNG) is its immunity to major attacks on pseudo-random number generators. The paper presents test results of proposed PRNG subjected to NIST SP 800-22 statistical test suite and also shows the performance comparison of proposed generator on different systems.

Privacy protection is of extreme importance especially in security sensitive environments. Neither cryptography nor steganography comes up with ultimate solution for privacy preservation in open systems. However, combination of steganography and cryptography can greatly increase the security of communication and is usually considered a good practice for securing security driven communication environments. In this paper we propose a novel scheme for image authentication and secret data sharing based on three level security model viz: Compression, steganography and cryptography. Compression optimizes the resource usage, steganography conceals the existence of message and cryptography is used to achieve confidentiality and authentication.