VRF Leader Election

Leader Selection in Consensus

In most Byzantine Fault Tolerant systems, a proposer is elected to produce the subsequent block in the chain. This function allows simplicity and minimized communication as the Validator Set decides on the contents of the next block.

→ However, if designed incorrectly — the network may be halted or tokens may be distributed unfairly, threatening the integrity and confidence of the entire system.

Distributed Denial of Service Attacks

💡A DDoS attack is a coordinated exploit where multiple sources overload a system by overwhelming a server with requests.

Performing a DDoS attack on a series of BFT leader would cause an extended non-liveness event for the chain — essentially halting the system.

An example of weak DDoS protection is any chain built with Tendermint / Cosmos SDK:

• Utilizes Round-Robin Leader selection which makes future leaders predictable as long as the set remains constant.

• Asks Validators to run 'Sentry Nodes' in front of any Validator to protect against this, but since Sentries also may be DDoS'd — this methodology is weakly effective at best.

Grinding Attacks

💡 A stake grinding attack (pre-computation attack) is an exploit where the current leader biases the future leader selection by modifying block contents or election parameters until they have a higher likelihood of being a future leader.

Executing a grinding attack on a blockchain system leads to significant bias in token distribution and control — effectively undermining the decentralization and fairness of the crypto-economy.

As many blockchains attempt to Randomness in the leader election to address DDoS attacks — they inadvertently cause another serious threat in Grinding Attacks:

• NXT

• Early Cardano

• Pre-Merge Ethereum

NestBFT Leader Election

NestBFT implements a DDoS resistant and highly available leader selection algorithm that is immune to grinding attacks:

• Mult-candidate

• Stake-Weighted

• Blind / reveal cycle

• Non-biasable seed input

→ By combining simplicity with cryptographic integrity, this design enhances security and resilience in decentralized environments.