How Does AuxPoW Leverage the Security of a Larger Blockchain?

Auxiliary Proof-of-Work (AuxPoW) allows blocks mined on a smaller chain (the secondary chain) to be simultaneously validated by the hash power of a larger, more secure chain (the primary chain, often Bitcoin or Litecoin). Miners on the primary chain can include the secondary chain's block header in their own block.

This means that to successfully attack the secondary chain, an attacker would need to overcome the combined hashrate of the primary chain, making a 51% attack economically unfeasible. It essentially piggybacks on the security budget of the dominant chain.