Increased necessitate for medical treatments and improved quality of care for people attributable to "Wireless Body Area Networks (WBANs)". The information obtained from the wearable sensors "Sensor Node (SN)" is generally stored in the server module. Challenges to the privacy of WBANs could originate from a multitude of sources due to the rapidly changing of the distributed system as well as the networking endpoints themselves. Mostly a set of biomedical parameters relevant to a patient's health are currently processed by the existing "Block Chain (BC)" technology. However, in BC, significant information will be lost in transmission and a lot of energy is used throughout the process of communication. Under this research, it provide a unique "Adaptive Dynamic Cryptosystem (ADC)" method centered on the "Data Encryption/Decryption Keys" paradigm to address privacy and security concerns. The proposed ADC method could support the management of clinical healthcare resources for patients from far areas by providing safe, privacy-protecting monitoring of patient activities. ADC is a flexible solution that can protect data of varying sizes. The patient's encrypted medical records are made available throughout the encryption procedure via the private key. For WBANs to be able to provide trustworthy remote patient monitoring services, the encrypting operation produce an encrypted message with a length of "n-bits". As a result, the suggested ADC method minimizes both the level of energy usage and the computation time. Utilizing health records as its foundation the proposed ADC provides a higher rate of data privacy and a higher security ratio. The suggested ADC method provides higher levels of security than the existing BC method in terms of "Security Ratio", "Energy Consumption Ratio", "Encryption Time" and "Decryption Time" as determined by the assessment methodologies used for both approaches.