Denial of Service (DoS) refers to an attack aimed at making a network service unavailable to users. In the context of cryptocurrency, this typically involves overwhelming a blockchain network with excessive requests or transactions to disrupt normal operations.Attackers can deploy various techniques, such as submitting a large number of transactions with minimal fees. This clogs the network, delaying legitimate transactions and leading to higher fees for users trying to send their coins. In a more severe form, a Distributed Denial of Service (DDoS) attack uses multiple compromised systems to launch a coordinated effort against a target. This can severely strain network resources, leading to downtime or degraded service quality. Such attacks can undermine user confidence and harm the reputation of the affected cryptocurrency, potentially impacting its value. As blockchains strive for scalability and speed, DoS attacks remain a significant concern for developers and investors alike.