The Kusama Network is secured using NPoS mechanism. This network of nominators elect nodes to participate in the transaction validation process. If the numerator is selected for the next generation then the nominator receives a fraction of inflation reward.
The stake of the validators is slashed if they do not meet performance requirements. Additionally, Kusama uses a simple queuing mechanism based on Merkle trees to solve cross-chain transactions. The Relay validators are responsible for moving the transactions from the output queue of one parachain to the input queue of the target chain.
The validators validate the data in the parachain blocks. They also take part in the voting and proposals for changes on the network. Nominators secure the Relay chain by selecting the validators. They delegate their staked tokens to the validators and thus allocate their vote for them.