Table 3 BC with FC integration limitations and future directions

Scalability [85, 98]

• As a result of the storing of network-wide transactions, the storage needs must be raised

• Latency remains an issue due to the huge amount of data processed

• Various consensus algorithms consume a lot of energy

• Block creation confirmation times are long

Security & Privacy [64, 90, 192, 200, 231]

• In most cases, user data in public BC is available to anybody

• Off-chain alternatives are still a source of contention

• Privacy problems arise as a result of pseudonymous techniques

Standards and regulations [85, 164, 232]

• It is necessary to create standards for building safe smart contracts that cannot be exploited for harmful reasons

• On a worldwide scale, competent and uniform rules and regulations are necessary

• Interoperability issue due to different consensus models, transaction methods, and smart contract functionality

Quantum, AI & Big Data [109, 233,234,235,236]

• Complex big data analytics techniques on limited resources are a significant problem for FC and BC

• Authenticating the training data sets might be a significant challenge

• Evaluation and standardization of post-quantum cryptography primitives are required