VRF Leader Election
Last updated
Last updated
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 or tokens may be distributed unfairly, threatening the integrity and confidence of the entire system.
💡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.
💡 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 attacks — they inadvertently cause another serious threat in Grinding Attacks:
NXT
Early Cardano
Pre-Merge Ethereum
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.