How Does Proof-of-Activity Prevent a 51% Attack?

Proof-of-Activity increases the difficulty of a 51% attack by requiring an attacker to control a majority of both the network's hash rate (PoW) and the circulating coins (PoS). In a typical PoW system, an attacker only needs a majority of the hash rate.

With PoA, even if an attacker mines a block, they would also need to be selected as a validator to approve it. The random selection of validators makes it statistically improbable for an attacker to both mine a block and have enough stake to be chosen to validate it.

This dual requirement significantly raises the cost and complexity of a successful attack.