Modified Transaction Against Double-Spending Attack Using Blockchain to Secure Smart Cities

Blockchain paves the way to fill the research gaps in terms of security, database process, cryptography, data center, etc. in the research fields like networking, big data and cloud computing in recent days. Generally, blockchain contains blocks of chain where each block is referring to the previous blocks and difficulty in the recreation of a chain. It provides a set of bitcoins, which is nothing but the digital currency utilized for cryptocurrency to manage several transactions based on a fully distributed environment. As bitcoins decentralizes for the mining process, mining processes are performed for the creation of bitcoin too. While considering the security, the bitcoin transaction has several attackers shows while making transactions. The most severe attack that we have found here is the double-spending attacks to modify and manipulate the transaction performed. Based on the blockchain framework existence, all the transactions stores into the transaction part of each block. Transactions perform a hash function which hashes each transaction and repeat it for pairing again and again based on the Merkle tree. Merkle tree is the block header that stores the hash of the previous block header. These chaining process helps the transaction to ensure no modifications done without changing the earlier blocks in the chain network. The transaction in blockchain denotes the bitcoin wallet, which tells the information about bitcoin's movement. Each spend transaction of bitcoin has the previous bitcoin transaction. Double spending attack occurs when a single transaction creates multiple output transaction while sending to several destination addresses. In the blockchain, each output transaction is provided based on one input. If any attempt of the same bitcoin uses for two or more times for a transaction, the double-spending attack is possible. Based on the existing survey related to the double-spending attack ratio, there is a possibility of a double-spending attack in the blockchain. Based on the double-spending attack problem, the modified bitcoin transaction chaining technique proposes with integrated the electronic codebook based on cryptography. As to provide more security, modes of electronic code operations are considered. Based on the block cipher of block length and in the case of multiple blocks of information are processed, security attacks are possible as block chaining added up into the transaction between the sender and receiver, which ensures authentication and confidentiality. The initial constant provides integrated with the transaction to provide maximum security and protect against unauthorized changes. To provide additional security constant number is considered as the random number which gets varied for each transaction based on output feedback mode operation.