The growth of the Internet of Things (IoT) has connected a massive number of devices, but its common centralized design creates major security, privacy, and scalability problems that old security methods cannot properly fix. This review explores how Blockchain Technology (BCT) offers a new approach to create trust and strong security for IoT systems without a central authority. Following the PRISMA guidelines, this study analyzes 68 research papers and uses a Chi-square test to statistically confirm the link between IoT problems and the use of blockchain solutions. The results show a strong, statistically proven connection, with a Chi-square value of 34.772 (p<0.05) and a Cramer's V of 0.63.... More >