The Internet of Things (IoT) becomes a leading field of computer science, which simplifies the life of human beings. The IoT, devices can interconnect and communicate with each other, in a fully autonomous mode. This autonomy has made the IoT network vulnerable to various security threats. However, due to this autonomy, there is a strong need for reliable security and storage mechanism for authentication to exchange data between IoT devices. To solve this problem, we propose an efficient method known as SCAB-IoTA, which ensures identification and authentication of IoT devices and also provides secure communication in the open environment. Along with authentication and secure communication, the scheme also ensures data integrity. SCAB-IoTA used the blockchain and hybrid cryptosystem (the combination of Advanced Encryption Standard (AES) and Elliptic Curve Digital Signature Algorithm (ECDSA) cryptographic techniques) to enhance the security of IoT applications to prevent various attacks along with less computational, and storage overhead. Furthermore, we have a secure cluster of IoT devices based on angular distance (AD), so that devices can securely communicate without any interruption. A secure and robust trust mechanism has employed to build these clusters, where each IoT device has to authenticate itself before joining the cluster. The obtained results satisfy the IoT security requirements with 60% reduced computation, storage and communication cost compared with state-of-the-art methods. The security analysis illustrates that SCAB-IoTA withstands against various cyberattacks such as impersonation, message replay, man-in-the-middle, and botnet attacks. © 2021 Elsevier Inc.