Research on mixing-based blockchain privacy and security focuses on techniques that enhance user anonymity and transaction confidentiality in decentralized networks. Mixing, or coin-mixing, protocols combine multiple transactions from different users to obfuscate the link between sender and receiver addresses, thereby mitigating traceability and protecting financial privacy. Studies explore various mixing strategies, including centralized mixers, decentralized mixing networks, and cryptographic approaches such as zero-knowledge proofs and ring signatures, to prevent deanonymization and resist attacks. Research also evaluates the trade-offs between privacy, scalability, and transaction efficiency, as well as the potential vulnerabilities that could be exploited by malicious actors. Overall, mixing-based solutions play a critical role in strengthening privacy, security, and trustworthiness in blockchain ecosystems.