Implementation of ChaCha20 Algorithm with Elliptic-Curve-Diffie-Hellman in Server Room Monitoring System to Prevent MITM and Reused Key Attack

A server room in a building or office usually stores essential items and must always be supervised, such as electronic devices, switches, routers, etc. One aspect of supervision in the server room is to keep the temperature and humidity stable so that the appliances in it will not be damaged due to temperatures that are too high. This supervision can be realized by creating a server room monitoring system using ESP32 and DHTII. The system can automatically display temperature and humidity data on the user interface via a smartphone. The system implements the ChaCha20 algorithm with the HTTP protocol. This algorithm tends to use the same key every time it is implemented, so in this study, additions be made to create a shared-secret key with a key exchange scheme using Elliptic Curve Diffie Hellman (ECDH). The results of the ChaCha20 and ECDH algorithms are used to ensure data confidentiality by encrypting the entire data to avoid Man-In-The-Middle-Attack (MITM) and Reused Key Attack attacks. From the results of attack testing, the ChaCha20 algorithm can prevent MITM attacks, and the application of ECDH to create a key or shared-secret for different encryption on each data transmission can prevent Reused Key Attacks.