Description Following the reading of the articles provided the discussion board, answer the following questions: 3a. Describe in your own words the three main capabilities that are supported by the blockchain implementation 3b. Explain in your own words the Blockchain Level transaction models, benefits and challenges related to security and privacy. 3c. Review the security and privacy Requirements of online transactions, list the seven types and outline how can blockchain transactions become vulnerable to various types of attacks (i.e. tampering, denial-of-service (DDoS), double-spending, majority consensus, and pseudonymity) 3d. Select two types of techniques and describe how they can be leveraged to enhance the security and privacy of existing and future blockchain systems 3e. Select two of the UN sustainable development goals and express how Blockchain technology will enable realizing these goals. * Provide 1 academic journal that is peer-reviewed and within 3 years old, and 2 industry source that are no older than 3 years to support your answers.