k-Buckets
Kademlia’s routing table structure: each node maintains bits (typically 160) k-buckets, where the i-th bucket holds up to k (typically 20) known peers whose XOR-distance from this node has its highest bit at position i. A peer for the i-th bucket shares an i-bit common prefix with the local node and differs at bit i+1. The least-recently-seen eviction policy biases bucket membership toward long-lived nodes, providing resilience against churn-based and Sybil-style attacks.