Deepti Sehrawat, Nasib Singh Gill, Analysis of Security Attacks on Lightweight Block Ciphers and their Countermeasures, Journal of Engineering and Applied Sciences, Volume 13,Issue 20, 2018, Pages 8439-8447, ISSN 1816-949x, jeasci.2018.8439.8447, (https://makhillpublications.co/view-article.php?doi=jeasci.2018.8439.8447) Abstract: Internet of Things is a global network based architecture utilizing sensor networks for communication between objects. Security and privacy are primary and essential requirements for network based application. Lightweight cryptography works for smart IoT environment by providing lightweight ciphers as a security solution. Cryptanalysis is another related field with the aim to explore cipher designs by revealing hidden factors like key, state of cipher and plain/cipher text. For this an attacker applies different attacks on a cipher. A cipher providing enough resistance against feasible attacks is considered as a good cipher. In lightweight cryptography, a cipher has to be lightweight in terms of resources and simultaneously it must provide good immunity against feasible attacks. This study summarizes various cryptographic attacks on lightweight block ciphers. Analysis of the effects of various attacks in such a smart environment is also presented in this study along with some countermeasures, so as to prevent from such attacks. This in turn, provides a sound foundation for new researchers wishing to gain an insight into IoT security. Keywords: IoT architecture;attacks;security;RFID;IoT layers;key technologies;threats;security solutions