Validator Sampling

Validator sampling is a process used in sharded blockchains where a subset of the total validator set is randomly selected to validate transactions within a specific shard. By randomly assigning validators, the network makes it computationally infeasible for an adversary to predict or manipulate which nodes will be responsible for a particular shard at a given time.

This randomness ensures that no single shard can be easily targeted or compromised by a concentrated group of malicious actors. If validators were fixed to a shard, an attacker could slowly accumulate enough stake within that specific shard to take control.

Sampling effectively increases the cost of an attack to a level proportional to the security of the entire network rather than just the individual shard. This mechanism relies heavily on secure, unpredictable sources of randomness.

It is a cornerstone of maintaining decentralization in high-throughput distributed ledgers.