This paper specifies the Staking module of the Cosmos SDK that was first described in the Cosmos Whitepaper in June 2016.
The module enables Cosmos SDK-based blockchain to support an advanced Proof-of-Stake (PoS) system. In this system, holders of the native staking token of the chain can become validators and can delegate tokens to validators, ultimately determining the effective validator set for the system.
This module is used in the Cosmos Hub, the first Hub in the Cosmos network.