How Do Cryptocurrency Exchanges Protect Themselves from 51% Attacks?

Exchanges employ several strategies to protect against 51% attacks and the resulting double-spends. They often require a higher number of block confirmations for deposits from smaller, more vulnerable coins, increasing the time and cost for an attacker to rewrite the chain.

They also monitor network hashrates for sudden, suspicious spikes and may temporarily halt deposits and withdrawals for a specific coin if an attack is suspected. Some exchanges participate in consortiums that share threat intelligence.

In the event of an attack, an exchange might delist the compromised coin to protect its users and itself from further losses.