Technical Details

1.7 billion adults have no access to the global financial system, while another 1.3 billion are underserved. Epic Cash unlocks human potential by connecting individuals to the global market. Fast, virtually free to use, and open to all

Privacy

The modern day use of money can be understood as the collective transference of units of account between people and institutions. The landscape of money at any given point in time can be mapped by answering the following questions:

  1. Who is holding it, and how much are they holding?
  2. Who is transacting with whom, and for how much?

For traditional fiat currencies, and indeed Bitcoin as well, we can answer those questions. In so doing, much can be revealed about people’s lives, such as consumption patterns, ownership, and transactional counterparties. Fairly accurate conclusions can be drawn about an individual’s interests and intentions by tracing transfers of value. Without privacy, transaction data can be dangerous information in the hands of predatory third parties.

The past decade’s use of cryptocurrency shows a continuum of “privacy” in varying blockchain implementations. The privacy scale, should one be considered, ranges from open and notorious on one end to anonymous on the other. As privacy erodes, one essential cornerstone of cryptocurrency, trustlessness, degrades. As evidenced by the success of Bitcoin blockchain analysis services, Bitcoin is situated more towards the notoriously transparent end of the privacy spectrum. Users must increasingly take steps to ensure they don’t inadvertently transact in tainted Bitcoin. The Epic Cash solution swings the needle towards anonymous and restores this essential property by ensuring that both the privacy of the individual and privacy of transactions are engineered into the system at a fundamental level.

Privacy of identity

Most cryptocurrencies like Bitcoin are stored in wallets whose addresses refer to public keys derived from a wallet’s private keys. These addresses can be thought of as locators of one’s private vault in the digital world. The Epic Cash blockchain eliminates addresses entirely and instead applies one grand multisignature from which all public and private keys are generated on a single-use basis.

Because Bitcoin wallet addresses are a vault’s locator in the digital world, that wallet can be traced to an owner’s Internet Protocol (IP) address, which anchors the owner to a computer at a unique location at a given point in time. Simply explained: when a Bitcoin transaction takes place, the transaction is broadcast from a communication hub called a ‘node’ and then propagated to other nodes called ‘peers’. That information then quickly spreads to each of those nodes’ peers consecutively across the entire network. This process is aptly named the “Gossip Protocol”. Quite simply, each Bitcoin has a visible online position and a physical location where it, or rather the Bitcoin owner, can be found. As journalist Grace Caffyn noted, Bitcoin is “no more secret than a Google search from a home internet connection.

In addition to eliminating wallet addresses, the Epic Cash blockchain secures privacy of identity by ensuring IP addresses can’t be traced. It does this through the integration of the Dandelion++ Protocol. Improving upon its predecessor, the original Dandelion Protocol, the Dandelion++ Protocol is a result of 7 researchers’ continued work to combat deanonymization attacks on the blockchain. Through Dandelion++, transactions are passed over random intertwined paths, or ‘cables’, and then suddenly diffused to a large network of nodes, like the pods of a Dandelion flower when blown from their stem (Figure 1). This makes it nearly impossible to trace transactions back to their origin, and thus their originating IP addresses.

Figure 1: Dandelion++ Communication

Privacy of transaction

The Epic Cash blockchain 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, methods in large part developed by Gregory Maxwell (Bitcoin Core developer, Co-Founder and CTO of Blockstream)

CT, originally created by Adam Back and later refined by Maxwell, 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, observers cannot see the actual amounts of the transactions 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.

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 Maxwell’s second concept, CoinJoin.

To illustrate CoinJoin simplistically, imagine that A, B and C are sending Epic to X, Y and Z, respectively. Sent through the CoinJoin medium, all that is known is that A, B and C are sending and X, Y and Z are 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

Privacy summary

The Epic Cash blockchain protects the privacy of individuals and their transactions by:

Eliminating wallet addresses

There are no location identifiers to digital vaults within the blockchain. Transactions are constructed directly person-to-person on a wallet-to-wallet basis;

Dandelion++ Protocol

Obscures the digital pathways of a transaction from the transaction sender’s IP address;

Confidential Transactions

Divide transactions into multiple pieces and introduce blinding factors into the collection of those pieces, so that the values of the pieces and other transaction parameters cannot be known;

CoinJoin

Combines transactions into bundles to mask the relationships between transacting parties.

Mining

The Epic Cash blockchain pursues decentralization by welcoming a wide variety of computation hardware. Epic mining is initially available to CPUs, GPUs, and ASICs, using three respective hashing algorithms: RandomX, ProgPow, and CuckAToo31+. Algorithms can be trivially hot-swapped without compromising the integrity of the chain.

RandomX & CPUs

RandomX is a Proof-of-Work (PoW) algorithm optimized for general purpose CPUs. It uses random code with several memory-hard techniques to achieve the following goals:

  • Prevention of the development of single-chip ASICs;
  • Minimize the efficiency advantage of specialized hardware over general purpose CPUs.

Mining Epic with CPUs requires a contiguous allocation of 2 GB of physical RAM, 16 KB of L1 cache, 256 KB of L2 cache, and 2 MB of L3 cache per mining thread. Windows 10 devices require 8 GB or more RAM. It is not inconceivable that one day in the not-to-distant future mobile phones could become viable mining nodes. Early CPU integration in the Epic Cash mining network is an excellent opportunity for many with only modest computing means to earn block rewards by helping to secure the Epic Cash network.

Progpow & GPUs

Programmatic Proof-of-Work (ProgPow) is an algorithm that depends on memory bandwidth and core computation of randomized math sequences, which take advantage of many of a GPU computing features and thereby efficiently capture the total energy cost of the algorithm. As ProgPow is specifically designed to take full advantage of commodity GPUs, it is both difficult and expensive to achieve significantly higher efficiencies through specialized hardware. As such, the ProgPow algorithm mitigates incentives for large ASIC pools to outcompete GPUs, as is often seen with many other PoW algorithms, such as Bitcoin’s SHA-256. GPUs, although not as prevalent as CPUs, are still commonly available. With technological development driven by powerhouses, Nvidia and AMD, GPUs are able to parallel process many multiples of mining solutions above CPUs on a per unit basis. It is due to this combination of ubiquity and high processing power that GPUs will provide the backbone to much of the mining activity during the initial eras, as indicated in Table 1.

CUCKATOO31+ AND ASICs

CuckAToo31+ is an ASIC friendly permutation of the Cuckoo Cycle algorithm developed by Dutch computer scientist, John Tromp. A relative of the ASIC resistant CuckARoo29, CuckAToo31+ generates random bipartite graphs and presents miners with the task of finding a loop of given length ‘N’ passing through the vertices of that graph.
This is a memory bound task, meaning the solution time is bound by memory bandwidth rather than raw processor or GPU speed. As a result, the Cuckoo Cycle algorithms produce less heat and consume significantly less energy than traditional PoW algorithms. The ASIC friendly CuckAToo31+ allows efficiency improvements over GPUs by using hundreds of MB of SRAM while remaining bottlenecked by memory I/O. Ultimately, ASICs offer the greatest potential economies of scale of the three mining options. In the interest of inclusivity, however, though they are allocated a small portion of mining rewards relative to CPUs and GPUs early on, eventually ASICs assume a majority stake of the mined block rewards, on the assumption there will be a competitive ecosystem of device manufacturers for CuckAToo31+.

Table 1: Mining reward allotments

Figure 2: Mining reward allotments

Mining contributions

Starting at the Epic Genesis (2019) and concluding at the Epic Singularity (2028), during the mining process, there is an allocation of Epic that is redirected, as mining contributions, towards the EPIC Blockchain Foundation.

The EPIC Blockchain Foundation is dedicated to technical development and promoting awareness and utility of the Epic Cash project during the early years of its inception, by creating marketing activities and developing partnerships within the financial technology industry.

After the Epic Singularity (2028), the EPIC Blockchain Foundation role will be assumed by the EPIC Distributed Autonomous Corporation (EDAC), that will be developed by the foundation prior to the handover.

The EPIC Blockchain Foundation is funded by a percentage of mining revenues, deducted from block rewards, according to the following annual rates:

Table 2: Annual rates for mining contributions as percentage of mining revenuess

Fungibility

Charlie Lee, the creator of Litecoin, stated that fungibility was the only property of sound money missing from Bitcoin and Litecoin, admitting that privacy and fungibility were the next battlegrounds for those coins. Andreas Antonopoulos, one of the world’s foremost blockchain experts, claimed that “…tainted coins are destructive. If you break fungibility and privacy, you break the currency.”

Fungibility is the property of a set of goods or assets that ensures the individual units of that set are of equal value and are interchangeable. It is what differentiates the earliest forms of currency from their preceding systems of barter. Without confidence in the fungibility of money, that money rapidly loses its utility. As will be illustrated below, the fungibility of most cryptocurrencies is uncertain, whereas Epic Cash’s privacy architecture ensures it is impervious to the same threats.

Most cryptocurrencies similar to Bitcoin, by the nature of the transparent blockchains on which they exist, can be verifiably traced through every wallet in which they were kept. Private third parties and governments alike monitor the Bitcoin blockchain with increasingly sophisticated means to quickly identify coins used in previous activities. This naturally leads to concerns that tainted coins might someday be banned from transactions, leaving their subsequent good-faith holders at a loss.

On March 19, 2018, the U.S. Office of Foreign Asset Control (OFAC) announced it was considering including digital currency addresses to the list of Specially Designated Nationals (SDN), which are entities with whom U.S. persons or businesses are forbidden to transact.

Even more troubling, the OFAC has not ruled out the inclusion of addresses currently holding tainted coins on to the SDN list, which would effectively place innocent owners of tainted cryptocurrency on a criminal blacklist due to the affiliation of the tainted coins owned. This has led New York University legal professor, Andrew Hinkes, to quip, “kiss fungibility goodbye,” and that the public should expect “a premium on freshly minted coins, or traced clean coins…

With these developments in mind, it’s not difficult to imagine an upheaval in the crypto market and the suffering, or even extinction, of many well-established cryptocurrencies. However, Epic is one of the few cryptocurrencies that avoids this problem entirely due to the strong privacy features previously described in this paper. By removing the link between identity and ownership, and the relationship between transacting parties, Epic can never be affiliated to a person or an activity. As such, the value of Epic remains independent of its users and provides high degrees of privacy and security that cannot be easily manipulated by malicious actors in criminal, financial, or political arenas.

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…TAINTED COINS ARE DESTRUCTIVE. IF YOU BREAK FUNGIBILITY AND PRIVACY,YOU BREAK THE CURRENCY.

ANDREAS ANTONOPOULOS

Scalability

Epic Cash is a MimbleWimble blockchain implementation that yields advances in scalability as a result of space efficient design that sheds redundant transaction data. The Cut-Through functionality responsible for this assures that the blockchain grows more space efficient over time unlike most cryptocurrencies, including Bitcoin, and that new nodes can be created with minimal investments in memory and computing power. By remaining space efficient, it capacitates a widely dispersed network and fosters decentralization. Furthermore, while each Bitcoin node must store the entire chain, Epic Cash nodes are able to contribute to network security based on a small subset of blocks.

Most cryptocurrencies require indefinite storage of all transaction data on their blockchains. The Bitcoin chain currently gains 0.1353 GB of memory each day, while Ethereum’s chain increases at an even faster rate of 0.2719 GB a day. If Bitcoin’s chain continues to grow at its current rate, it will eventually reach an approximate 6 TB in size by the time its last block is mined in the year 2140. Ethereum will surpass 10 TB by that date. In most blockchains without MimbleWimble, transactions must be verified by nodes all around the world. As data increases, so does the burden on each node. Even at only 200 GB (the approximate size of the current Bitcoin chain), synchronizing the data requires a stable network and high-speed disk read and write capability.

Consequently, mining has become increasingly centralized among large pools leveraging costly computing resources. If the entire blockchain history of Bitcoin were to be stored on the Epic Cash blockchain instead, it would fit into nearly 90% less space. Smaller is faster because each transaction requires less time to transmit and secure.

MimbleWimble solves this storage dilemma with an innovative method of block pruning, referred to as ‘Cut-Through’. In order to understand how Cut-Through works, it’s best to first look at how transactions and blocks are composed within a MimbleWimble blockchain.


All Epic Cash transactions include the following parts:

Inputs

Reference to old outputs;

Outputs

Confidential Transaction outputs and rangeproofs;

Excess

The difference between outputs and inputs, plus signatures (for authentication and to prove non-inflation).

Figure 3:
MimbleWimble transaction parts

All Epic Cash blocks contain:

In Figures 3 and 4, adapted from Andrew Poelstra’s presentations, we can see newly mined Epic represented as the broken-white input cells. Identically colored cells represent outputs with corresponding spent inputs. With the Cut-Through process, inputs and matching spent outputs are removed to free up space within the block, which reduces the amount of data that needs to be stored on the blockchain. While the transactions are omitted from the ledger, the remaining excess kernels (a mere 100 bytes) permanently document that the transactions took place.

As blocks continue to be created, MimbleWimble applies Cut-Through across blocks, so that over the long run all that remains are the block headers (approximately 250 bytes), unspent transactions, and transaction kernels (approximately 100 bytes). Grin, the second MimbleWimble implementation to be launched, showed that a MimbleWimble chain with a similar number of transactions to the Bitcoin chain would be nearly 10% of the size of Bitcoin’s chain. Furthermore, the size of a node will be “on the order of a few GB for a Bitcoin-sized chain, and potentially optimizable to a few hundred megabytes.”

This stands in marked contrast to Bitcoin, where the entire blockchain must be stored by each node. Over time, as the space efficiency of the Epic Cash blockchain grows relative to the Bitcoin blockchain, so too will the cost efficiencies relative to the participation of nodes in the Epic Cash network. Lower barriers to participate helps ensure crucial resilience at the node layer of network design.

Through its implementation of MimbleWimble and application of chain pruning with the Cut-Through process, the Epic Cash blockchain offers scalability in a way often overlooked by the cryptocurrency community. It is one that captures the essence of Bitcoin and like-minded projects: decentralization. Regardless of how many transactions per second a coin might be able to process, what good is it if it can’t be sustained by a broad and diverse network? If memory requirements are such that validation ultimately gravitates towards strong mining conglomerates, then all of the cryptocurrency community’s efforts to create a decentralized ecosystem are obviated. To provide for additional throughput capacity, the Epic Cash development roadmap provides for a Lightning-style Layer 2 implementation as a near term objective.

Figure 4:
MimbleWimble transactions before and after Cut-Through

Monetary policy

The monetary policy of Epic Cash and Bitcoin are very similar. The Epic circulating supply first expands rapidly and then synchronizes with the circulating supply of Bitcoin in 2028. It increases thereafter at a declining rate until reaching a maximum supply of 21 million Epic by 2140. Epic has the qualities to become a safe store of long-term value because the circulating supply is known at any point along its emission lifecycle and culminates in a fixed maximum supply. The Epic Cash monetary policy is characterized by the following four features:


Rapid emission over the first nine years of its lifespan, during which 20,343,750 Epic (96.875% of the total supply) are to be mined. The exact emission rates are outlined in the Emission Schedule section of this paper;


The Epic circulating supply and emission rate synchronize with those of Bitcoin on the Epic Singularity around May 24, 2028. Following the Singularity, the emission rate decreases at an increasing rate, while the circulating supply grows at a decreasing rate;


A maximum supply of 21 million Epic is reached in year 2140, at the same time as Bitcoin reaches a maximum supply of 21 million units;


Epic has an 8 decimal divisibility structure, such that: 1 Epic is equal to 100,000,000 Freeman (just as: 1 Bitcoin is equal to 100,000,000 Satoshi).

The Epic Cash monetary policy is modelled after Bitcoin’s for the following reasons:

Agreement with the economic fundamentals of Bitcoin, namely that scarcity and predictability of circulating supply underlie its strong store of value properties


The public is already familiar with Bitcoin’s model and its proven track record over the last ten years since its inception. By approximately synchronizing with Bitcoin’s circulating supply, and mirroring Bitcoin’s maximum supply and divisibility structure, Epic takes the path of least resistance towards mass adoption.

Emission Schedule

Epic Cash has a total of 33 mining eras, each defined by decreases in block rewards, relative to their preceding era. The Epic Genesis, the date on which the first Epic Cash block is mined. Blocks are mined at one per minute. The first five eras produce nearly 97% of the Epic maximum supply, matching 20 years of Bitcoin emissions in approximately nine years. This can be thought of as a chance to ‘turn back the clock’ for those who missed out on the spectacular rise of Bitcoin.

The emission schedule in Table 3 outlines the start and end dates of the first seven mining eras, their corresponding block rewards, and the ensuing circulating supplies for each era. The eras 8 to 33 are not included in the table for brevity’s sake. For those eras, it should suffice to understand that each subsequent era will have a block reward that is half the amount of the reward of the preceding era, exactly as in Bitcoin. The amount of Epic emitted during each of these eras will be the sum of block rewards within the 4-year era (approximately 1460 days).

At the Epic Singularity (2028), the Epic circulating supply intersects the number of Bitcoin’s circulating supply, at which point Epic Cash adopts the Bitcoin block reward and halving pattern, which sees block rewards decrease by half every four years. The only exception is that Epic blocks continue to be mined at a rate of one each minute, versus Bitcoin’s rate of one block every ten minutes. By doing this, the Epic circulating supply maintains approximate parity with Bitcoin’s circulating supply for the remainder of their existence.

Table 3: Emission schedule for the first seven mining eras.

Figure 5: Epic and Bitcoin emission schedules.

Technical specification

Project Name

Epic Cash

Currency Name

EPIC

Block time

60 Seconds

Block Size

1MB

Starting Supply

0

Final Supply

21,000,000

Consensus

RandomX (CPUs), ProgPow (GPUs) and CuckAToo31+ (ASICs)