Blockchain security is a comprehensive risk management system that includes assurance services, cybersecurity frameworks, and best practices to reduce the risks of fraud and cyberattacks. In shortened, an inherent data structure with security features is produced by blockchain technology where it is founded on cryptographic, decentralized, and consensus principles that uphold transactional trust. As our technology continuously updates and changes, new techniques and methods are appearing to secularly keep user details. The "Blockchain-based system" is among the finest. In a blockchain-based system is nearly impossible to hack or leak someone's information without permission. This is a more secure and reliable system than most of the other systems. But as this is a new and growing technology few online courses industry is using the system but not with its full function. We suggested including blockchain technology in the system of "Online courses". As a security precaution, the course modules and details will be entered into it, two keys are used throughout the entire program. The first is the public key, which is necessary for our course title and description, and the second is the private key, which is necessary for each course module and the payment system. Multiple machine learning models like Linear regression, random forest that are used to detect fraudulent transactions in the application. Every block and user details were hashed (64 bits) to keep them unique from each other. Numerous applications and software projects have been secured by blockchain technology. During our research, we experimented in a novel way and developed a fresh methodology that can be more secure than previously used applications. In this instance, our machine learning models have performed well so far, and we have also gained high accuracy from our dataset while.