#CryptoSecurity101 #CryptoSecurity101 Cryptocurrencies are emerging as virtual financial systems based on their innovative decentralized and distributed strategy in order to provide astonishing capabilities across a range of applications. In contrast to the conventional currencies that exacerbate security threats, these threats have been implicitly addressed by the notion of cryptocurrencies, which have a distinguished impact on their adoption rate among stakeholders. However, this potential adoption bubble may get diminished by the uncontrolled fragility in market conditions and persuasive increase in potential contemporary security concerns. In this survey, we systematically examine the state-of-the-art associated with security concerns in cryptocurrencies from various perspectives. Firstly, we investigate state-of-the-art consensus mechanisms, as they are one of the primary underlying concepts of cryptocurrencies. Thereafter, we thoroughly investigate various applications of cryptocurrencies. Subsequently, we present a detailed examination of various contributions from the literature addressing security aspects in cryptocurrencies. We also shed light on some of the well-known ongoing cryptocurrency-related projects across the globe. Furthermore, we outline open challenges and draw insights for perspective directions of research in the domain.