The crypto community knows that a 51%-attack is possible and has been working to develop effective defenses.

The following are some of the most promising strategies:

• Use Alternative Consensus Mechanism
  Avoid relying on proof-of-work, and instead adopt consensus mechanisms such as Proof-of stake that enhance security and reduce electricity consumption. The blockchain will be more eco-friendly and scalable, as it will reduce energy costs and improve network security.

• Promoting Decentralization
  The more nodes involved in maintaining consensus, the harder it is to consolidate control power. Many initiatives have reward systems in place to encourage the additions of new nodes.

• Keen Observation Of Mining Activity
  Observe mining activities more closely to detect fake nodes and potential attacks before they happen. This analysis allows for the rapid identification of power concentrations that may be suspicious.

• Specialized mining methods
  ASIC mining requires the use of expensive specialist equipment. The cost of technology to gain 51% control of Bitcoin's hashrate is estimated at billions, making it financially impossible.

• Real-Time Monitoring
  Monitoring of blockchain in real-time to detect suspicious activity immediately. These systems allow for quick action in the case of an attack. It restricts and monitors the abuse of rented hashrate by speculative pools. This reduces vulnerability to attacks.