RapidChain is a sharding-based public blockchain protocol that improves upon existing solutions by achieving high throughput and security. It partitions nodes into smaller groups called committees, allowing parallel processing of transactions and reducing communication, computation, and storage overhead. RapidChain is resilient to up to 1/3 of the nodes being corrupted and achieves complete sharding of communication, computation, and storage without requiring a trusted setup. It uses an optimal intra-committee consensus algorithm, a novel gossiping protocol for large blocks, and a provably-secure reconfiguration mechanism to ensure robustness. RapidChain avoids gossiping transactions to the entire network by using an efficient cross-shard transaction verification technique. Empirical evaluations show that RapidChain can process over 7,300 transactions per second with an expected confirmation latency of about 8.7 seconds in a network of 4,000 nodes, with an overwhelming time-to-failure of over 4,500 years. RapidChain operates in a permissionless setting, allowing open membership without assuming an initial common randomness. It uses a decentralized bootstrapping approach to establish identities and join committees. The protocol uses a synchronous consensus algorithm to achieve optimal resiliency of 1/2 within committees, allowing a total resiliency of 1/3. It also uses a reconfiguration mechanism based on the Cuckoo rule to allow new nodes to join the protocol seamlessly. RapidChain's cross-shard verification technique allows each node to store only a fraction of the entire blockchain, reducing storage requirements. The protocol uses an efficient inter-committee routing protocol to discover and communicate with other committees. RapidChain's consensus protocol is designed to handle large blocks efficiently, using a gossiping protocol and a Merkle tree to ensure consistency and verify transactions. The protocol is evaluated and compared with state-of-the-art sharding-based protocols, showing significant improvements in throughput and latency.RapidChain is a sharding-based public blockchain protocol that improves upon existing solutions by achieving high throughput and security. It partitions nodes into smaller groups called committees, allowing parallel processing of transactions and reducing communication, computation, and storage overhead. RapidChain is resilient to up to 1/3 of the nodes being corrupted and achieves complete sharding of communication, computation, and storage without requiring a trusted setup. It uses an optimal intra-committee consensus algorithm, a novel gossiping protocol for large blocks, and a provably-secure reconfiguration mechanism to ensure robustness. RapidChain avoids gossiping transactions to the entire network by using an efficient cross-shard transaction verification technique. Empirical evaluations show that RapidChain can process over 7,300 transactions per second with an expected confirmation latency of about 8.7 seconds in a network of 4,000 nodes, with an overwhelming time-to-failure of over 4,500 years. RapidChain operates in a permissionless setting, allowing open membership without assuming an initial common randomness. It uses a decentralized bootstrapping approach to establish identities and join committees. The protocol uses a synchronous consensus algorithm to achieve optimal resiliency of 1/2 within committees, allowing a total resiliency of 1/3. It also uses a reconfiguration mechanism based on the Cuckoo rule to allow new nodes to join the protocol seamlessly. RapidChain's cross-shard verification technique allows each node to store only a fraction of the entire blockchain, reducing storage requirements. The protocol uses an efficient inter-committee routing protocol to discover and communicate with other committees. RapidChain's consensus protocol is designed to handle large blocks efficiently, using a gossiping protocol and a Merkle tree to ensure consistency and verify transactions. The protocol is evaluated and compared with state-of-the-art sharding-based protocols, showing significant improvements in throughput and latency.