Internet of Things (IoT) is a network convergence of multiple intelligent devices and advanced technologies aiming at connecting and exchanging data over the Internet. IoT is extensively applied in consumer, commercial, industrial, infrastructure and military spaces. With the prevalence of IoT applications, security issues such as identity authenticity and data privacy are increasingly become critical concerns. Authentication and confidential data sharing are the important measures towards secure IoT communication and applications. Blockchain is a burgeoning technology supporting for efficient authentication and secure data sharing. A secure and accountable data transmission scheme based on blockchain has been proposed by Hong et al. recently. But this scheme has security weaknesses of impersonation attack, man-in-the-middle attack, replay attack, denial of service attack (DoS) and key compromise attack. Thus we put forward an improved scheme to overcome the identified security flaws. Our scheme is provably secure and performance analysis shows that our scheme reduces 15.34% computation costs and 40.68% communication costs compared with Hong et al.’s scheme. Meanwhile, we also compare our scheme with other three recent and related researches, which finally indicates that our scheme realizes a well tradeoff between security and efficiency.

物联网（IoT）是多种智能设备和先进技术的网络融合，旨在通过Internet连接和交换数据。物联网广泛应用于消费，商业，工业，基础设施和军事领域。随着物联网应用的普及，诸如身份真实性和数据隐私之类的安全性问题日益成为人们关注的重点。身份验证和机密数据共享是实现安全的IoT通信和应用程序的重要措施。区块链是一种新兴技术，支持有效的身份验证和安全的数据共享。Hong等人提出了一种基于区块链的安全可靠的数据传输方案。最近。但是该方案存在模拟攻击，中间人攻击，重播攻击，拒绝服务攻击（DoS）和密钥泄露攻击。因此，我们提出了一种改进的方案来克服已发现的安全漏洞。我们的方案可证明是安全的，性能分析表明，与Hong等人的方案相比，我们的方案减少了15.34％的计算成本和40.68％的通信成本。同时，我们还将我们的方案与其他三项近期和相关研究进行了比较，最终表明我们的方案实现了安全性和效率之间的良好折衷。