Epic Cash assures transaction privacy by obscuring amounts and the sender-receiver relationship of a transaction. This is achieved through the application of ideas familiar from Confidential Transactions (CT) and CoinJoin.
CT works by breaking transactions into smaller parts through homomorphic encryption, a method of performing calculations on encrypted information without decrypting it first to preserve privacy. Once divided up, the actual amounts of the transactions cannot be seen because of blinding factors, a system that throws random numbers into the mix of transaction fragments to conceal the values of those fragments. Ultimately, only transacting parties know the value of an exchange, while the transaction is verified by the network through confirmation that the sum of the output values equals the sum of the input values, and the sum of the output blinding factors equals the sum of the input blinding factors. Epic Cash assures transaction privacy by obscuring amounts and the sender-receiver relationship of a transaction. To further complicate the task of prying eyes, all Epic Cash transactions are cloaked with CT and then mixed together to hide the connections between transacting parties. This is done through CoinJoin. To illustrate CoinJoin simplistically, imagine that A, B, and C are sending Epic Cash to X, Y, and Z, respectively. Sent through the CoinJoin medium, all that is known is ABC is sending and XYZ is receiving, while the transaction amounts remain invisible. The CoinJoin system is fundamental to Epic Cash through One-Way Aggregate Signatures (OWAS), which combine all transactions inside a block into a single transaction.