  Cryptocurrencies based on decentralized systems, especially blockchain, are
gaining popularity more than ever. Freedom advocates hail blockchain technology
as a breakthrough in digital privacy and internet anonymity. Unfortunately,
after recent studies conducted, it may come as a surprise that the transactions
are, in fact, not always anonymous. In this short paper, the possibility of
identifying a user's accounts in different cryptocurrencies given the user's
portfolio of investment gained from social media is investigated. In this
study, the generic elements of blockchain systems are briefly studied. In
section \ref{sec:blocksim}, BlockSim which is a tool for simulating
transactions, and an algorithm for answering this question is introduced.
