Research On New Type Of Covert Communication Model And Methods In Blockchain Environment

Traditional covert communication uses a centralized channel for data transmission,relying on third-party central nodes or authoritative organizations to achieve data packet distribution and security assurance.Its channel is easy to be monitored and the communication is easy to be detected,interfered,and attacked.When the central node is not trustworthy,the transmitted data will be leaked or even tampered with.As an emerging decentralized technology,blockchain has been more and more developed in recent years.Its distributed chain storage,anti-interference,anti-detection,and anonymity can effectively alleviate the problems faced by traditional covert communications.In addition,once data is recorded in a block,it cannot be tampered with.It is necessary to find a way to enable confidential information to be safely and secretly transmitted in the open and transparent blockchain.To this end this paper proposes a covert communication model in the blockchain environment by studying the characteristics of the blockchain and traditional covert communication model,and designs feasible information steganography and covert transmission methods for different application scenarios and platforms in the blockchain.Major initiatives include:Firstly,from the point of view that most of the existing covert communications use centralized channels,this article analyzes the limitations of traditional covert communications and derives the advantages of using blockchain for covert communications.The covert communication model under the blockchain and the current research status of covert communication and blockchain are introduced.Secondly,this paper improves on the BLOCCE,a covert communication method using Bitcoin public key addresses,to design a more efficient and practical method V-BLOCCE in order to solve the problems of low information embedding and transmission efficiency and high cost in the existing covert communication methods implemented using Bitcoin transactions.This method encodes the information in base58 and uses the Bitcoin address generated by vanitygen as the information carrier,embedding the information in the form of character matching.The order of address usage and information restoration rules are passed through the OP RETURN field of the Bitcoin transaction.The experimental results show that this method has higher information embedding efficiency,information transmission efficiency and lower cost than the original method.Thirdly,since there is no feasible implementation method for blockchain-based covert communication in Ethereum,this paper studies the whisper,a secure communication protocol for distributed applications of Ethereum,and proposes an efficient and feasible method of information concealment transmission in combination with the structure of the basic unit of information transmission and the protocol flow.This method interacts with the topic-key pairs required for communication covertly and uses the payload of the letter body as an information carrier to match characters with the ciphertext while using padding to store the generated index.The interacted key is used to encrypt the content of letter which is added redundant information according to the protocol's default filling rules.The letter is broadcast to achieve communication after being construct with topic.The experimental results show that the proposed method can resist the interference of the network and letters of the same subject.It has anti-tampering and anti-detection properties,and is also better than traditional methods in terms of data embedding and transmission efficiency and cost.Fourthly,from the perspective of the diversity of parameters and data redundancy of Ethereum smart contracts,a covert communication method in the blockchain environment that uses smart contracts as information carriers is designed.It uses the parameters in the contract to map the secret information sequence and transfers the message through the deployment and invocation of the contract,combining with encryption algorithms and two-round protocols to protect data privacy.In addition,voting and bidding contracts are combined to instantiate the proposed model,and two optimized versions of the contracts are also proposed to reduce costs.Redundant options,effective price ranges,and fake bids are set in two contracts to increase redundancy.Experimental results show that the proposed method has tamper resistance and low complexity,and it is feasible to use it for covert communication.