Due to its decentralized nature and encryption methods, blockchain technology is generally secure. When a block has been approved and added to the chain, it cannot be removed. Furthermore, all transaction information is encrypted, making it almost impossible to penetrate and obtain stolen data, even if the network is hacked. 

However, blockchain networks are still susceptible to a variety of cyberattacks, including 51% attacks, routing attacks, Sybil attacks, and phishing attacks. A 51% attack occurs when a group of miners with control of more than half of the network’s computing power abuses the ledger, causing fraudulent transactions or effects. 

Routing attacks involve stealing data from blocks by intercepting it while it is being transmitted to another node, either to extract information stored on the network or steal funds from transactions. Sybil attacks occur when an attacker creates several false identities in order to gain control of the network. Phishing attacks are aimed at stealing funds and credentials from the user by impersonating someone else directly. 

Best practices in cybersecurity are important to defend against the myriads of attacks on blockchain networks. This includes proper identity and access management, continual risk assessments, using a VPN to conduct secure transactions, and having unique dedicated antivirus software for each system to guard against common threats to security. 

Blockchain security is important for providing authorization and protection for sensitive data, even if there are existing vulnerabilities. In the broader sense, blockchain security is different from cybersecurity, as the focus is on preventing blockchain-specific attacks, like 51% attacks or Sybil attacks, as opposed to protecting all systems, as would traditionally fall under cybersecurity. 

Although blockchain is designed to be secure, the risks associated with the possibility of these attacks discriminate against the need for appropriate blockchain security threat risk mitigation strategies.