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Integrating Monero P2Pool Mining into ServUO and Alternative XMR-to-BCH Reward Pipeline

Michael Ten 60 min read
Dragon fountain of the Cantonese Assembly Hall

Here is a proof-of-concept and production-level feasibility for integrating Monero’s P2Pool into the ServUO emulator, as well as the extended pipeline involving Monero-to-Bitcoin Cash conversion and smart contract distribution using CashScript. Also provided a detailed report covering technical implementation, in-game trigger design, reward distribution, non-custodial architecture, and comparisons between the two options.

Also included are architecture descriptions, relevant code or pseudocode examples, and highlight any similar projects (if any exist) that incorporate Monero or Bitcoin Cash in gaming environments.

Introduction: This report examines how to integrate Monero’s decentralized mining pool P2Pool with the Ultima Online server emulator ServUO, enabling in-game actions to contribute to mining and reward players with cryptocurrency. We explore a direct integration of Monero (XMR) P2Pool mining into ServUO (both as a proof-of-concept and a production design), and then an alternative pipeline where mined XMR is converted to Bitcoin Cash (BCH) and distributed via smart contracts on the BCH blockchain. Key technical requirements, trigger mechanisms, reward distribution methods, and challenges are analyzed for both approaches. Pseudocode, code snippets, and architectural insights are provided to illustrate how such an integration can be implemented in a non-custodial, automated fashion.

Technical Feasibility of P2Pool Integration in ServUO

P2Pool Overview: Monero’s P2Pool is a decentralized mining pool that runs on a peer-to-peer “share chain” separate from the main Monero chain. Each P2Pool node works with a local Monero daemon and allows miners to collaborate without a central pool operator. Importantly, miners receive payouts directly in the Monero block reward when a block is found, according to shares they submitted. This means no pool custodians hold funds – all payouts are trustlessly encoded in the block’s coinbase transaction to the miners’ own addresses. This architecture eliminates the need to trust a pool and mitigates regulatory pressure on a central operator.

ServUO Environment: ServUO is an Ultima Online server emulator written in C# .NET. Being open-source, it allows custom C# scripts and plugins to extend game functionality. We can feasibly integrate a mining mechanism by adding a “Mining Manager” component to the server. This would handle: (a) connecting to a P2Pool node (likely via the Monero mining stratum protocol), (b) performing hash computations (using Monero’s RandomX proof-of-work algorithm), and (c) submitting valid shares to the P2Pool network. The integration can leverage ServUO’s event system to trigger mining (discussed next), and .NET’s multithreading to perform hashing without stalling game logic.

Requirements: The server (or its host machine) needs to run a Monero full node (daemon) and a P2Pool instance. The Monero node can run in pruned mode (≈54 GB blockchain) to save space. P2Pool itself requires about 2.6 GB RAM (or ~0.6 GB in light mode) plus minimal disk space. In a production setting, both the Monero daemon and P2Pool node would ideally run on the same host as ServUO for low-latency communication (P2Pool default binds to localhost). Firewall rules should allow the Monero P2P port (18080) and P2Pool port (37889 for regular or 37888 for “mini” mode) for network connectivity.

Integration Architecture: There are two primary ways to integrate the mining logic with ServUO:

  • 1. Stratum Client Approach: Treat ServUO as a mining client. P2Pool provides a Stratum-like interface on port 3333 for miners. ServUO’s Mining Manager can open a TCP socket to 127.0.0.1:3333 and perform the mining handshake. In Monero’s Stratum protocol, the mining client typically sends a login with a target address. However, Monero’s P2Pool ignores the miner-specified address and instead uses the address supplied when the P2Pool node was launched. This means a single P2Pool instance, by default, credits all shares to one wallet address (the --wallet address given at startup). We will revisit this limitation in the challenges section. For now, assume a one-address P2Pool.

  • 2. Direct Mining Library Approach: Integrate a RandomX hashing library or invoke an external miner in controlled bursts. Monero’s RandomX PoW can be executed via a C/C++ library. We could use P/Invoke or a C# wrapper to call into such a library for hashing. Alternatively, ServUO could spawn an external miner process (like xmrig) configured to connect to P2Pool. For a proof-of-concept, starting a background xmrig process with low CPU intensity is simplest. For a tighter integration, implementing the mining loop in C# is possible but would require porting or binding to the RandomX algorithm (which is non-trivial but feasible with existing C++ implementations).

Implementation Steps: Assuming the Stratum client approach with an external or internal miner, the high-level integration steps are:

  • Setup Monero and P2Pool: Start the Monero daemon (pruned) and then launch the P2Pool node. For low-hashrate scenarios, use P2Pool “mini” mode (--mini) which lowers share difficulty so that small miners can find shares more frequently. For example: ./p2pool --host 127.0.0.1 --wallet <ServerWallet> --mini (ServerWallet here is a placeholder address for testing). Wait for P2Pool to sync its mini share-chain (~5–10 minutes).

  • Extend ServUO Scripts: Create a new C# class (e.g., MiningManager) within the ServUO script system. This manager maintains connections to P2Pool and orchestrates hashing tasks. It might contain:

    • A persistent TCP connection to the P2Pool’s stratum port.
    • Code to parse mining jobs (the Monero block template and target difficulty) provided by P2Pool.
    • A RandomX hash function to compute hashes on given nonces.
    • A mechanism to submit found shares (nonce + result) back to P2Pool via the stratum protocol.

  • Event Hooking: Modify relevant game event handlers (combat, mining skill use, crafting completion, etc.) to notify the MiningManager. For example, when a monster is killed or ore is mined, call MiningManager.QueueWork(player, difficultyContribution) to assign some hashing work “credit” to that player’s address.

  • Hashing Execution: The MiningManager should asynchronously perform the hashing so as not to stall game logic. One design is to maintain a background thread (or task) that continuously processes a queue of mining work:

    // Pseudo-code for MiningManager event handling
class MiningManager {
    // Queue of pending work items
    ConcurrentQueue<MiningTask> taskQueue = new ConcurrentQueue<MiningTask>();
    // Start a background thread to consume the queue
    public void Start() {
        Task.Run(ProcessQueueLoop);
    }
    public void QueueWork(Player player, int hashesToCompute) {
        var task = new MiningTask(player.WalletAddress, hashesToCompute);
        taskQueue.Enqueue(task);
    }
    private async Task ProcessQueueLoop() {
        ConnectToP2Pool();  // open socket to 127.0.0.1:3333
        var currentJob = GetLatestJob();  // from stratum, contains block template & target
        while (true) {
            if (!taskQueue.IsEmpty && taskQueue.TryDequeue(out MiningTask task)) {
                // Perform the hash computations for this task
                await ComputeHashesAsync(currentJob, task);
                // (If a valid share is found during ComputeHashesAsync, submit via socket)
            } else {
                await Task.Delay(50);  // small delay to prevent tight loop
            }
        }
    }
}

    In the above pseudocode, whenever QueueWork is called (from a game event), a number of hashes are scheduled. The background loop fetches the latest mining job (block header data and target difficulty) from P2Pool and then computes the specified number of hashes. If any hash meets the share difficulty target, it is immediately submitted to P2Pool over the stratum connection. The use of Task.Run and async ensures the game’s main thread is not blocked – mining runs in parallel on other CPU cores.

  • Player Wallet Management: Each player who participates in mining should provide a Monero wallet primary address (P2Pool does not support using Monero subaddresses for mining). In a non-custodial setup, players generate their own XMR wallets, and input their address into the game (perhaps via a command or account setting). The server then knows which address to credit for a given player’s mining contributions. One simplistic approach is to run a separate P2Pool instance per player, each with that player’s address – however, this is resource-intensive and not scalable. A more practical approach is discussed under challenges (since P2Pool currently uses a single address per node).

  • Testing (Proof-of-Concept): In a controlled environment, one could start ServUO and verify that when a player triggers an event, the MiningManager successfully computes some hashes and (ideally) finds a share. The share discovery can be logged, and using the P2Pool Observer tool, one can check that the player’s address shows up with submitted shares. Keep in mind that at low hashrate, finding a share is probabilistic – P2Pool mini mode should be used to make this feasible (e.g., a few kH/s might find a mini share every few hours rather than days).

Best Practices:

  • Utilize P2Pool Mini for low to moderate hashrates. The mini share-chain yields more frequent (but smaller) payouts and is recommended for hashrates below ~50 kH/s. For example, a miner at 10 kH/s might only find a regular P2Pool share every ~2.7 days, but on P2Pool mini they’d find one every ~2.8 hours, greatly smoothing the reward flow.
  • Run P2Pool in --light-mode to reduce RAM usage to ~0.6 GB, which is useful if the game server machine has limited memory or is hosting many instances.
  • Offload heavy hashing to background threads and consider using native code for the RandomX inner loop. RandomX initialization is memory-heavy (it uses ~2GB scratchpad); reuse the initialized VM across hashes if possible. The P2Pool node itself can be run with --no-cache if not mining on the node, to reduce RAM (though if our ServUO is doing the mining, we might not need P2Pool’s internal miner at all, just the stratum server).
  • Ensure proper exception handling and timeouts on network calls to P2Pool – the MiningManager should handle cases like P2Pool node restarting or network lag (perhaps by reconnecting or re-fetching jobs periodically).
  • Use thread throttling or a rate limit for hashing if needed to balance game performance. For example, one might cap the total hashes computed per second based on server CPU headroom. In production, dedicating specific CPU cores to mining threads (and leaving others for game logic) can isolate performance impact.
  • Security: Running a Monero node and P2Pool on the same server means exposing it to the internet (for P2Pool’s P2P connectivity). Keep these components updated to avoid vulnerabilities, and consider sandboxing the mining processes. Since ServUO will be interacting with these processes, validate all data from P2Pool (though the stratum protocol is fairly simple, any untrusted data should be handled cautiously).

In-Game Trigger Mechanisms for Hash Computation

In this system, not every second of CPU time is spent mining; instead, game events act as triggers for mining bursts. This ensures mining activity is tied to player engagement, aligning with a “play-to-earn” concept.

Possible Trigger Events:

  • Combat Actions: e.g. defeating a monster or participating in PvP. When a creature dies, the server’s code (e.g., the OnDeath event of the creature’s script) can award a certain amount of “hash power” to the player who dealt the final blow (or distribute among participants). For instance, killing a tough monster might enqueue a larger chunk of hashing work than an easy one, reflecting a higher reward.
  • Resource Gathering: e.g. mining ore, chopping wood. If a player successfully mines an ore vein using the mining skill, this could trigger a hash computation related to literal mining. This is an intuitive mapping: in-game mining yields in-game ore and kicks off some Monero mining in the background. Similarly, crafting an item or completing a quest could trigger some hashes as a “reward.”
  • Time or Action Interval: Instead of one hash burst per action, the system could accumulate actions over a time window. For example, every minute of active play grants X hashing operations, to be executed continuously. However, a one-to-one event mapping is simpler and more transparent to players (“kill monsters, earn hashes”).

Balancing Frequency: We need to balance game performance with mining efficacy:

  • If triggers are too frequent or assign too many hashes, the server could become CPU-bound, causing lag.
  • If triggers are too sparse, players will generate very few hashes, resulting in rare or negligible payouts (given the difficulty of finding shares).

A reasonable strategy is to tie the number of hashes to the significance of the event. For example:

  • Defeating a boss might trigger 100,000 hash computations.
  • Killing a regular monster: 1,000 hashes.
  • Mining one unit of ore: 500 hashes.
  • Crafting an item: 100 hashes.
    These values can be tuned in playtesting. They effectively throttle how much mining occurs. We can also impose a global rate limit (e.g., at most 1 million hashes per minute across the entire server) to guarantee the game loop isn’t starved.

Asynchronous Execution: All hash computations should run asynchronously. The pseudocode earlier illustrates queueing tasks. In practice, one could use the .NET ThreadPool or Task library. Another pattern is to use a producer-consumer model: game events produce “mining work tokens” and a dedicated consumer thread performs the work.

Example pseudocode inside ServUO for an event hook:

// In a Mob class or combat system script:
public override void OnDeath(Container corpse) {
    base.OnDeath(corpse);
    if (LastKiller is PlayerMobile player) {
        // Award hash work based on monster fame/karma (difficulty)
        int hashCount = this.Fame / 10 + 1000;  // e.g., scale by monster strength
        MiningManager.Instance.QueueWork(player, hashCount);
    }
}

In ServUO, OnDeath is a common override for when a mobile (creature) dies. The above pseudo-code grants the player a number of hashes proportional to the monster’s fame (a measure of difficulty in UO). The MiningManager.Instance.QueueWork call then adds that work to the mining queue for asynchronous processing, as described.

Optimal Timing: It might be tempting to execute mining immediately on the game event thread (for example, directly in OnDeath). This should be avoided – hashing even 1000 RandomX operations can take significant time (RandomX is CPU-cache heavy). Always offload to a background thread to keep the game responsive. The game thread should merely signal the work and then continue with normal logic (looting, XP award, etc.).

Player Feedback: Consider how players know they are earning crypto. The game could provide feedback such as “You feel a surge of energy… (Hash power +1000)” in the in-game text, or a GUI element showing accumulated hashes or “mining contribution.” Because actual XMR payouts may be infrequent, providing an estimated reward or share count can motivate players. For instance, track how many P2Pool shares each player has submitted, and display it periodically. Players can also be instructed to check their Monero wallet for direct payouts once blocks are found (or use the P2Pool Observer with their address to see progress).

Rate Limiting and Exploits: We must anticipate that players might try to game the system:

  • Macroing trivial actions: If killing easy monsters yields hashes, someone might script kills of trivial creatures endlessly to farm XMR. To counter this, tie hash rewards to meaningful actions or put a cap on repetitive actions. Perhaps after X kills in an hour, the hash reward diminishes (to prevent infinite farming).
  • Multi-client abuse: If one physical person runs many game accounts in parallel to multiply earnings, this could overwhelm the server. The server admin might enforce limits (like one mining-enabled account per IP, etc.) if necessary.
  • Difficulty and Reward Scaling: This integration blurs game economy with an external crypto economy. It’s important for gameplay balance that the pursuit of crypto doesn’t undermine the in-game progression. Ideally, the crypto rewards are a bonus that enhances the game’s appeal, not the sole purpose of playing (unless the server is explicitly a play-to-earn shard).

Trigger Frequency Tuning: A possible frequency approach is to make hashing time-based with boosts:

  • Run a background miner thread constantly at a low level (say, 10 H/s per active player).
  • When a trigger event occurs, temporarily boost the hash rate for a short burst.
    This ensures continuous participation in P2Pool (so the server is always mining at least a bit, reducing variance) and still ties spikes to gameplay. However, continuous mining might still consume resources. Many implementations will stick to purely event-driven mining for simplicity.

In summary, in-game triggers should be carefully selected and calibrated to provide a fair and engaging experience, where players’ normal activities naturally contribute to mining over time. Using ServUO’s flexible scripting, we can integrate these triggers at key points (combat, resource gathering, achievements) and adjust the “hash credit” each action yields.

Rewards Distribution via P2Pool and Non-Custodial Benefits

One of the most attractive aspects of using Monero’s P2Pool is the non-custodial reward distribution. Unlike a traditional game rewards system (where the game might send cryptocurrency from its own wallet to players, implicating custodial management), here the mining itself handles payouts:

  • Direct Payouts to Players: Each valid share a player contributes will count toward a portion of a future block mined by the P2Pool network. When P2Pool eventually finds a Monero block, the block’s coinbase transaction will include outputs paying every miner who had shares in the last window (PPLNS – Pay-Per-Last-N-Shares – is typically used). The payout is direct to the Monero addresses that earned it. Neither the game server nor any third party ever holds those XMR; it’s created in the block and sent to the player’s wallet by the Monero protocol.

  • Trustless Pooling: Because P2Pool maintains a decentralized ledger of shares (the P2Pool side-chain), miners cannot be cheated out of rewards. All P2Pool nodes verify each share and the payout calculations. There is no central pool operator who might withhold funds or require withdrawals – rewards are simply delivered on-chain when due. This solves the compliance problem for the game developer: since the game isn’t dispensing rewards (the mining process is), the game operators likely do not qualify as money transmitters or fall under virtual asset service provider regulations. They are providing software that enables players to mine on their own behalf.

  • Privacy and KYC/AML: Monero is a privacy-focused cryptocurrency; P2Pool’s payouts preserve that privacy. There is no KYC because there is no exchange or custodian – players just provide an address. Monero addresses are not trivially linkable to real-world identity (especially if users create a fresh address just for this game). Moreover, P2Pool decentralization means there is no single entity for regulators to target to enforce KYC or bans. This is a compliance advantage: the reward system sidesteps the need for the game to collect personal information or deal with financial regulations, since it’s analogous to players’ computers finding blocks solo (just cooperatively). As noted by the Monero community, removing centralized pools also removes easy choke points for regulation or censorship.

  • Non-Custodial Nature: Non-custodial means players have full control of their funds. As soon as a payout is made to a player’s wallet, it’s their Monero – the server cannot freeze or claw it back. This is beneficial for player trust. It also means any value earned is outside the game’s economy (which could be seen as a pro or con). In terms of security, the game server becoming compromised does not put player XMR at risk (since the server never stores private keys or tokens on behalf of players). The worst a hacker could do is perhaps divert new mining work to their own address (a risk we should mitigate by code review and perhaps server admin alerts if the configured addresses change unexpectedly).

Verification of Rewards: A player can verify their rewards by checking their wallet for incoming XMR. P2Pool payouts occur whenever the P2Pool network finds a block (currently Monero blocks every ~2 minutes). If the server’s hashrate is small, it might take many blocks (hours or days) before one is found by P2Pool. When it is, if the player had at least one share in the last N shares, they will receive a proportional output. There is no “pending balance” on P2Pool – either you get included in the next block’s coinbase or you wait for the block after, etc. This means players might see nothing for a while then suddenly e.g. 0.01 XMR appear when a block hits.

Compliance Benefits (Detail): Traditional MMO cash-out systems could be seen as gambling or prize awarding, raising legal concerns. Here, players are simply mining cryptocurrency by playing. It’s analogous to folding@home or SETI@home style distributed computing being rewarded, rather than the game “paying” the player. Since Monero mining is permissionless and P2Pool is just a protocol, the game dev is not brokering any asset transfer. Additionally, Monero’s fungibility and P2Pool’s design inherently avoid the collection of personal data – even IP addresses are obscured if the player or server uses Tor/I2P (Monero P2Pool can run over Tor for privacy). By avoiding custodial wallets or in-game token economies, we also avoid potential classification of the game’s currency as a security.

Address Management: We should note that P2Pool currently requires a primary address (95-character Monero address starting with 4... or 8...). Subaddresses (Monero’s feature for generating many per-account addresses) aren’t supported for mining. This means if a player wants to use a new address for privacy, they should actually create a new Monero wallet (or at least a new account within their wallet). For compliance and privacy, advising players to use a fresh wallet for the game might be wise (so their other funds aren’t tied to their gaming activity). P2Pool makes addresses public on the share chain (for payout calculations), which is another reason to keep your “game mining address” separate from your personal one.

Example Workflow: Player Alice provides her Monero address to the game. After some hours of play, she has contributed say 5 shares on P2Pool. The P2Pool network finds a block. The coinbase transaction of that Monero block might have, for example, 20 outputs – one is destined to Alice’s address, amounting to her share of the 0.6 XMR block reward (Monero block reward as of 2024 is ~0.6 XMR, tail emission). Alice’s wallet will show an incoming transaction of maybe 0.03 XMR (if her shares represented ~5% of the pool’s effort in the last window) – directly from mining, not from the game operator. The game could also log a message like “Monero block found! Alice earned 0.03 XMR” if it monitors P2Pool’s status.

In summary, integrating P2Pool provides a built-in payout mechanism that is decentralized and non-custodial. It not only benefits players by giving them real cryptocurrency directly, but it protects the game operator from the complexity and liability of handling those funds. This approach leverages Monero’s strengths (privacy, decentralization) to create a seamless bridge between gameplay and crypto rewards, in compliance-friendly fashion.

Potential Challenges and Considerations

While the idea is compelling, there are several challenges and considerations to address in implementing P2Pool mining in a game:

1. Multi-Address Mining Limitation: As noted, one P2Pool instance uses a single wallet address for payouts. This is a fundamental limitation – P2Pool wasn’t designed as a multi-tenant service; rather, each miner is expected to run their own node or connect to one with their address. This poses a challenge for a server that wants to mine for multiple players concurrently. Possible approaches:

  • Multiple P2Pool Nodes: In extremis, run a separate P2Pool instance for each player’s address (on different ports). Each instance would connect to the same monerod backend. This would allow proper credit, but it’s inefficient in resource usage (each node eats RAM and bandwidth) and could become unsustainable beyond a handful of players.
  • Round-Robin Mining: A single MiningManager could rotate through player addresses, effectively pretending to be one miner for each player in quick succession. For example, every second, switch which address is set in P2Pool, or alternate connections. However, P2Pool doesn’t allow switching the address on the fly easily – it’s set at node start. One trick: Don’t run a local P2Pool at all; instead, have the game connect to remote community-run P2Pool nodes that allow miner-specified addresses. In practice, the official P2Pool software ignores miner-specified addresses to prevent mistakes, but a modified node or a “proxy” might accept them. There is a known project “p2pool-proxy” for Monero that could potentially allow connecting multiple miners to P2Pool using different addresses (by running mini P2Pool instances under the hood). This is speculative – currently, the straightforward way is one address per P2Pool node.
  • Custodial-then-Distribute (Not ideal): Have the server mine to its own address, accumulate rewards, and then split them among players off-chain. This reintroduces custody (and the very compliance issues we wanted to avoid), so it’s not a preferred solution. However, later in this report we discuss an alternate pipeline where converting XMR to BCH and using smart contracts could allow an automated distribution – which is a kind of delayed distribution mechanism.

Given this challenge, one might choose to frame the integration differently: for example, treat the guild or entire server as the mining unit. All players collectively mine to one address (perhaps owned by the guild leader or a smart contract). Then the reward is shared through some governance. This, again, trades off individual non-custodial payouts for a group-based approach. We will explore a trustless way to do group distribution in the BCH section.

2. Server Performance Impact: Mining is CPU-intensive. Running RandomX hashing on the same machine hosting an MMO server can lead to competition for resources. Mitigations:

  • Use nice/low priority threads for mining tasks, so the OS will give game-related threads priority on CPU time.
  • Limit the number of concurrent mining threads. If the server has N cores, you might dedicate at most N-1 cores to hashing at any time, leaving one core always free for game logic.
  • Monitor server tick timing – if frame/loop processing times start increasing, scale back mining.
  • Profile and possibly use hardware-specific optimizations (RandomX benefits greatly from large L3 caches and fast memory; a server CPU with many cores and a large cache is ideal).
  • Optionally, run the mining on a separate machine: e.g., the ServUO server could send “work orders” to another service (could be a custom C++ service or even an embedded Python script using Monero mining libraries) to handle the hashing. This way, if the mining box lags, it doesn’t affect game response. Communication could be via a local network socket or message queue. This adds complexity but is an option for scaling.

3. Game Design Balance: Introducing monetary rewards can alter player behavior. Some considerations:

  • Influx of “gold farmers”: You might attract players who only care about the crypto reward and not the game itself. They might use scripts or do only the minimal activities to maximize hashes. If XMR value is significant, this could become a form of mining botting. The game should have measures to detect and prevent automated farming if it degrades the game’s integrity.
  • Reward vs Effort: We must accept that as an incentive mechanism, the XMR earned may often be quite small (especially if only CPU mining on a single server). For example, if the server and players collectively manage 20 kH/s on P2Pool mini, they might get a few tens of dollars of XMR per month at current rates. If split among many players, it’s pennies per person – more of a fun bonus than an income. It’s important to communicate this so players view it as a perk rather than a livelihood. On the flip side, if the game becomes popular and somehow achieves higher hashpower, the admin should be wary of essentially subsidizing a lot of mining on their hardware without returns (unless perhaps the server owner also takes a small cut of the hashes to fund server costs – which could be done by occasionally mining to the admin’s address).
  • Game Economy: Ultima Online has its own gold economy. If players can earn crypto, will they start valuing in-game gold vs XMR exchange rates? It might even spur an exchange market where in-game items trade for Monero outside of the game. This could be interesting but also could destabilize the in-game economy if not monitored. It effectively introduces a real-money trading vector (which exists anyway in MMOs, but here it’s built-in).

4. Security Considerations:

  • Monero Node exposure: Running a Monero node means you have an open port (18080) for P2P. Ensure it’s properly firewalled (only needed if you want to contribute to the network; P2Pool can work with just outbound connections, though more connectivity is better). The node’s RPC (typically on 18081) should be bound to localhost only and secured; if an attacker accessed it, they could disrupt the backend.
  • P2Pool software: P2Pool is relatively new (Monero’s implementation was released in 2021 by developer SChernykh). Use the latest version for bug fixes. There is a chance of software bugs – an unchecked buffer or similar could pose a risk if the game server communicates directly with it. Running P2Pool under a restricted user account or container can limit damage from a potential exploit.
  • Game server logic: The integration code itself must be robust. For instance, if a player provides a malformed Monero address or a very high hash request (perhaps via some exploit), ensure the MiningManager validates inputs. Monero addresses have a checksum, so invalid ones should be rejected upfront.
  • Denial of Service: A malicious player could try to spam actions purely to overload the server with mining tasks. Rate-limiting per player and overall, as discussed, will mitigate this. The server could also maintain a “mining budget” per player per hour.
  • Cheating the Mining: Since mining shares can’t be faked (the solution either meets difficulty or not), there’s no way for a player to cheat the crypto side without doing the work. But a player might try to fake game events (exploit a bug to trigger combat events rapidly, etc.). Thus, standard anti-exploit patches in the game are important – this feature doesn’t necessarily introduce new exploits but could amplify the incentive to find exploits in the gameplay.

5. Variance and Player Perception: With mining, rewards are probabilistic. A player might play for days and not see any payout, then suddenly get a chunk. This variance might be confusing or discouraging to some.

  • To handle this, consider transparency: show players their contribution (e.g., “You have 0.005 shares in the pool” or “Your expected payout if a block is found now is X MRU (Monero Reward Units)”).
  • Possibly implement a local “points” system in parallel: e.g., for every hash computed, give the player some non-crypto points in-game which they can accumulate and maybe exchange for small cosmetic rewards. This way even if the crypto hasn’t hit yet, they feel progress. (This is optional but can improve player retention).
  • Education is key: since Monero is not widely understood by all gamers, providing a guide or command in-game like “[Crypto Help]” explaining how the mining and payout works will manage expectations.

6. Legal Considerations: While non-custodial, one should still consider if introducing crypto rewards could classify the game in certain ways (sweepstakes laws, gambling laws if random payout? Likely not, since it’s skill/action-based and everyone who participates will eventually get something – it’s not a lottery where some get all and some none). Also ensure players are of age as required for crypto in some jurisdictions. These are minor issues given no purchase is required and it’s essentially like “mining while playing,” but a thorough analysis should be done if the game is public.

In conclusion, the integration is feasible but requires careful engineering and design tuning. The major technical hurdle is the multi-address issue for P2Pool – which might push us to innovate or accept some compromises (like group mining). Performance is the other big factor; however, by leveraging modern multi-core CPUs and writing efficient code, a moderate amount of mining can be done without severely impacting the UO server’s function. We now turn to an alternative approach that addresses some of these challenges by using a different pipeline (XMR→BCH conversion and smart contracts) for reward distribution.

Alternative Pipeline: XMR-to-BCH Conversion and Smart Contract Distribution

In this alternative design, we decouple the mining reward currency from the reward distribution mechanism. The idea is:

  1. Players still mine Monero via P2Pool (as above) because Monero’s RandomX is ideal for CPU mining.
  2. The XMR mining rewards are converted to Bitcoin Cash (BCH) through a decentralized, non-custodial exchange process (using platforms like Haveno or atomic swap protocols such as UnstoppableSwap).
  3. The converted BCH is deposited into a CashScript-based smart contract on the BCH blockchain.
  4. That smart contract then automatically distributes the BCH to players (or guilds) based on in-game events or predefined rules, in a trustless manner using on-chain logic.

This pipeline is more complex but offers some benefits:

  • Bitcoin Cash supports smart contracts (albeit not Turing-complete like Ethereum, but capable for certain conditions). This allows implementing custom reward distribution schemes (e.g., pooling rewards for a guild achievement or splitting funds among members) that would be impossible on Monero’s blockchain (Monero has no equivalent smart contract capability).
  • BCH has fast transactions and low fees, making on-chain distribution practical. It also has an ecosystem of tools (CashScript, CashTokens, etc.) to program contract behavior.

We will break down this pipeline into components:

1. XMR to BCH Conversion via Decentralized Exchanges (Haveno, Atomic Swaps)

Haveno DEX: Haveno is a decentralized exchange being built on Monero (forked from Bisq) focused on privacy. It uses a peer-to-peer network and multi-signature escrows to facilitate trades without custodians. Haveno allows trading Monero for other assets (including BTC, BCH, fiat currencies) by matching buyers and sellers. Trades involve both parties placing funds in a 2-of-3 multisig (with a third-party arbitrator key in case of dispute), and then exchanging funds when both sides fulfill the conditions. Because it’s non-custodial and over Tor, it preserves privacy and avoids KYC in most cases.

Unstoppable Swap (Atomic Swaps): An alternative to the escrow model is atomic swaps, which are smart contracts/protocols enabling trustless exchange between chains. For Monero↔Bitcoin-family coins, atomic swaps have been implemented by projects like COMIT and Farcaster. The UnstoppableSwap project (and related BasicSwap DEX) provides tools to swap XMR for BTC or BCH without an intermediary. In an atomic swap, both parties either both get each other’s coins, or nothing happens – no partial completion is possible. Cryptographic tricks (hash time lock contracts on BTC/BCH side and key reveal on Monero side) ensure that if one side redeems funds, the other can too, or else a timeout refunds the initiator.

Conversion Workflow: There are a few ways to integrate conversion:

  • The game server (or an associated service) can act as the agent that converts XMR to BCH. For example, suppose all players mine to a server-owned Monero wallet (this introduces custodial step for conversion, but possibly handled by a multi-sig controlled by game devs). Periodically, the server sees it has, say, 1 XMR accumulated from mining. It then creates a trade on Haveno or triggers an atomic swap to exchange that 1 XMR for equivalent BCH.
  • Alternatively, each player individually could convert their XMR to BCH (opting in to the pipeline). But coordinating many small trades is inefficient, and players might not bother. It makes sense for the game as a whole to convert a pooled amount to BCH, then redistribute on BCH chain.
  • A hybrid approach: have one “exchange wallet” that all mining rewards go into (either directly via P2Pool mining to that address, or via players manually sending their small outputs to it for conversion). That wallet is then used for the conversion process.

Given our goal of non-custodial and automated workflow, we can design the conversion as follows:

  • The server’s Monero wallet (could be a multi-sig controlled by game admins to reduce single-point custody) is listed as the seller on Haveno, offering XMR for BCH.
  • A buyer on Haveno takes the offer and posts BCH.
  • Haveno’s protocol uses a multi-sig escrow: the XMR seller deposits XMR into an escrow on Monero (in Haveno’s case, perhaps simply locking it until trade completes), and the BCH buyer deposits BCH into an escrow address on BCH.
  • Once both are locked, and payment details are confirmed, the trade completes: XMR is released to buyer, BCH to seller (game’s wallet). If something goes wrong, the arbitrator key can assist, but assuming no dispute, it’s trustless beyond the need for a potential arbitrator who cannot steal funds (multi-sig escrow ensures they can only cosign a refund or completion).
  • The net result: the game’s wallet ends up with BCH in the amount of the converted mining rewards.

Atomic Swap approach: If using atomic swaps directly (UnstoppableSwap / BasicSwap):

  • The game server would run a swap client (taker) which connects to a swap provider (maker) advertising a BCH<->XMR swap. For example, the server wants to swap 1 XMR for BCH. It finds a maker willing to trade at current rate.
  • The atomic swap protocol executes: often, the BTC/BCH side locks up coins in a contract with a hash lock and time lock, then the XMR side sends Monero to a one-time address constructed with key shares (as described in research). Once XMR is sent, the BCH contract can be claimed by the XMR sender, revealing a secret that allows the other party to claim the XMR. If anything fails, refunds occur after timeouts.
  • The tooling for this (e.g., COMIT’s swap CLI or BasicSwap’s API) would need to be automated. The game server could periodically run a script that checks XMR balance and if above a threshold, initiates an atomic swap using the CLI. The output would be BCH sent to an address the server specifies.
  • Notably, with atomic swaps, we can specify the BCH output address to be the smart contract address where we want funds to end up. This way, as soon as the swap completes, the BCH is in the contract ready for distribution, and the server never “held” the BCH in a normal wallet at all. We’d need to ensure the atomic swap tool supports sending to a P2SH or CashToken contract address (likely yes, since it’s just an address format).

Automation and Tools: Both Haveno and atomic swap implementations can potentially be automated:

  • Haveno is still under development, but it’s essentially a headless daemon with an API (Bisq has JSON-RPC APIs; Haveno likely will as well). A script could use Haveno’s API to create offers, monitor trades, and finalize them. Haveno’s roadmap suggests it’s aiming to be user-friendly, but for our purposes we treat it as a back-end service.
  • UnstoppableSwap’s CLI (the COMIT team’s asb tool) can be scripted. BasicSwap DEX similarly might allow RPC control.

Challenges in Conversion:

  • Slippage and Rates: When trading XMR for BCH, we have to consider exchange rates. Haveno would use market pricing (from offers) which could have spreads. Atomic swaps rely on finding a partner; if liquidity is low, the rate might be poor. The game might end up converting at a loss if not carefully done. Perhaps treat this as a cost of the reward mechanism.
  • Fees: Haveno trades will incur transaction fees on both chains and possibly a trading fee (though Haveno itself doesn’t take fees beyond miner fees). Atomic swaps similarly have on-chain fees for the transactions (e.g., the BTC/BCH HTLC and the Monero transaction). These should be accounted for. Ideally, convert larger chunks infrequently to amortize fees (rather than many tiny swaps).
  • Timing: Haveno trades might take minutes to hours to find a peer; atomic swaps also can take some time (they require confirmations – e.g., XMR might wait 10 blocks (~20 min) and BCH 1 block (~10 min) in a protocol). This introduces delay in the reward pipeline. It might be fine if done asynchronously (players don’t expect instant conversion).
  • Security: Using Haveno or atomic swaps introduces complexity. However, they are non-custodial mechanisms, so the main risk is either trade failure (which just results in refund of funds to original parties) or, in Haveno’s case, needing arbitration if a dispute (which could slow things but not steal funds).

Compliance: Converting privacy coin XMR to BCH might ironically reduce privacy (BCH is pseudonymous, not anonymous). But if we then distribute via smart contract, everything on that side is public anyway. The conversion itself, if done via Haveno, retains privacy (Tor, no KYC). If via atomic swap, it’s also private (no third party, though the on-chain transactions are visible – one could potentially link the XMR and BCH addresses through timing correlation, but that’s fairly advanced analysis and beyond scope for game context). The pipeline remains KYC-free.

In summary, the game would incorporate an automated conversion service that periodically swaps mined XMR to BCH in a decentralized way, preparing the funds for on-chain distribution.

2. CashScript Smart Contracts on BCH: Capabilities and Constraints

Bitcoin Cash Smart Contracts: Bitcoin Cash (BCH) uses a scripting system inherited from Bitcoin. It is not Turing-complete and does not support arbitrary loops or persistent storage like Ethereum does. However, BCH has expanded its scripting capabilities through recent upgrades, adding opcodes for introspection and covenants (restrictions on how outputs can be spent) and features like CashTokens (which enable tokenization and more advanced smart contracts). CashScript is a high-level language that makes writing BCH scripts easier, with a syntax inspired by Solidity.

Capabilities:

  • BCH scripts can enforce complex spending conditions on UTXOs. With new introspection opcodes, a contract can examine the transaction that is spending it, including number of inputs/outputs, their values and locking scripts. This enables covenants, where the contract ensures that the next transaction (the spending transaction) has certain properties (e.g., pays to specific addresses).
  • Multi-signatures, hash locks (HTLCs), time locks (absolute via OP_CHECKLOCKTIMEVERIFY and relative via OP_CHECKSEQUENCEVERIFY) are supported. CashScript provides global variables like tx.time and tx.age to work with timelocks.
  • The CashTokens upgrade (May 2023) introduced the ability to create and manage tokens and even NFTs on BCH, and improved covenants by allowing scripts to access more data.
  • CashScript code is compiled to a Bitcoin Script that is then used typically in a Pay-to-Script-Hash (P2SH) or Pay-to-Script-Hash-32 (P2SH32) address. Users (or the game server) fund that contract address with BCH, and later the contract conditions must be met to spend from it.

Constraints:

  • No loops or dynamic code execution: Smart contracts on BCH cannot perform unbounded iteration or recursion. All logic must be resolved in one transaction validation. This means, for example, you cannot iterate over an arbitrary list of players on-chain; you might need to hard-code or put a fixed maximum.
  • No global state: Each contract is just the UTXO itself. To have state, it must be carried through via outputs. For instance, if you want a contract to remember something, you actually encode it into an output of a transaction, effectively creating a new UTXO with that data locked by the same script or a modified script.
  • Contract size and complexity: There are limits on script size (currently BCH allows larger scripts than BTC, but there’s still a byte-size limit and an execution step limit). CashScript abstracts a lot, but if you have a contract that checks many conditions (like paying out to 100 addresses with specific amounts), the script could become large or hit the limit of allowed opcodes executed. BCH’s recent upgrades (like BigNumber arithmetic) improved some capabilities but one must still ensure the contract is efficient.
  • Debugging and Tools: CashScript offers a debugging mode for testing, but deploying to mainnet requires careful verification. There is no concept of “reverting” a transaction on-chain if a bug is found – you’d have to deploy a new contract (i.e., use a new address with corrected script for future funds).

Despite constraints, BCH contracts are powerful enough for our purposes: they can ensure non-custodial distribution of funds by encoding the rules of distribution in the contract. The logic we might need:

  • Check that certain in-game conditions are met (which likely requires an oracle or an off-chain signature because on-chain script itself has no knowledge of game events).
  • Split outputs among multiple addresses in predetermined proportions.
  • Possibly enforce time constraints (e.g., only allow distribution after a certain date, or only once).

CashScript Example: To illustrate the flavor, here’s a simplified example of a CashScript contract that would pay out to two guild members equally, only when both a leader’s approval signature is provided and a certain “achievement code” is revealed (simulating an oracle):

pragma cashscript ^0.8.0;
contract GuildReward(pubkey leaderPubKey, bytes20 member1, bytes20 member2, bytes32 achievementHash) {
    function distribute(sig leaderSig, string achievementSecret) {
        // Require leader approval
        require(checkSig(leaderSig, leaderPubKey), "Leader must sign off");
        // Require the correct achievement secret
        require(sha256(achievementSecret) == achievementHash, "Secret mismatch");
        // Covenant: enforce exactly two outputs: one P2PKH to member1, one to member2
        require(tx.outputs.length == 2);
        bytes25 expected1 = new LockingBytecodeP2PKH(member1);
        bytes25 expected2 = new LockingBytecodeP2PKH(member2);
        // Each member gets half of the contract value (within 1 satoshi for odd amounts)
        int half = int(this.value / 2);
        require(tx.outputs[0].lockingBytecode == expected1 && tx.outputs[0].value >= half);
        require(tx.outputs[1].lockingBytecode == expected2 && tx.outputs[1].value >= half);
    }
}

In this pseudo-code:

  • leaderPubKey is the guild leader’s public key (they act as an oracle or approver).
  • member1 and member2 are the hash160 of the two members’ pubkeys (to create P2PKH addresses).
  • achievementHash is the hash of a secret string that corresponds to a guild achievement.
  • The distribute function requires a signature from the leader and the correct secret to unlock.
  • It then uses covenants: tx.outputs[i].lockingBytecode and .value to ensure the spending transaction pays out to member1 and member2 in equal parts.
  • this.value is the total satoshi value of the current contract UTXO (CashScript uses this.value internally to mean the value being spent).
  • If any condition is not met, the require will fail and the transaction is invalid.

This example shows the power: the contract can enforce the exact payout addresses and minimum amounts, ensuring the funds can only go to those guild members (and not be stolen by anyone, not even the leader, unless they collude to input a wrong secret or something, but if secret is tied to an event, they can’t fake it).

Comparison to Ethereum: On Ethereum, one could write a much simpler solidity contract that stores balances, etc., but it would require gas fees for each user action, and the game would need integration with Ethereum wallets. BCH’s approach is UTXO-based: stateless but highly secure and scalable (BCH can handle many TXs cheaply). The trade-off is complexity in encoding logic in a constrained script. However, as shown, typical distribution logic is achievable. We simply might not do extremely fancy things like dynamic loop over N players – we’d either limit the number of participants or have separate contracts per group.

One constraint: if a guild has many members, listing all their addresses in a single contract script might be cumbersome. One approach could be to use a Merkle tree or hash commitments of addresses, but BCH script doesn’t easily verify Merkle proofs without loops (there is a technique with recursion via Unspent outputs, but that’s advanced). A simpler approach: if guild size is moderate (say up to 5 members), just hard-code in contract. For larger distribution (like server-wide event for 100 players), it may be better to have the server break it into multiple payouts or use an off-chain calculation with an oracle signature for each person.

CashScript Limit Example: CashScript cannot loop, but we can chain conditions with if/else for a fixed number of cases. We might do something like:

require(tx.outputs.length == N);
require(tx.outputs[0].lockingBytecode == new LockingBytecodeP2PKH(member1) && tx.outputs[0].value >= amount1);
// ... similar requires for each member

This is fine if N is small. If N is large (like 50), the contract might become too large in bytes or hit limits. We may then split the funds into multiple contracts or have the game execute multiple transactions.

Overall, BCH smart contracts (via CashScript) can implement non-custodial reward distribution with certain constraints:

  • They can enforce the who and how much of payouts reliably.
  • They may rely on an oracle (like the guild leader or the server providing a signature or secret) to trigger the payout when an off-chain condition is met (since on-chain can’t directly know “guild cleared dungeon X” unless encoded as a secret or fed in via a signature).
  • They keep everything transparent: anyone can see the contract and verify that funds will only go to the intended recipients, which can build trust in the community (no hidden mechanics).
  • There’s no ongoing gas cost like on Ethereum – only the normal BCH transaction fees when a payout transaction is made, which are very low (fractions of a cent).

Now, having looked at the tools, let’s design how the pooled fund and contract distribution would work in practice.

3. Pooled Fund Distribution Models (Guild and Event Rewards on BCH)

By converting the mining rewards to BCH and pooling them in smart contracts, we can reward collective in-game achievements or coordinate distribution in more creative ways than per-share payouts:

Guild Mining Pool: Imagine each guild in the game has opted to participate in pooled mining. Instead of individual members mining for themselves, all their mining rewards (post-conversion to BCH) go into a guild fund contract on BCH. This guild fund could be used in a few ways:

  • Periodic payout: The contract might allow automatic splitting among members every week or month, perhaps weighted by their contributions. The weight could be determined off-chain (the server tallies each member’s contribution hash rate) and then constructs a transaction that pays each member accordingly, which the contract verifies (using covenants to enforce those outputs).
  • Achievement-based: The contract might stipulate that funds are locked until the guild accomplishes some milestone in-game. Upon completion, a guild officer (oracle) triggers the release to all members. This creates a “treasury” that incentivizes cooperative play.
  • Guild vs Guild competitions: One could even envision a contract that pools rewards from multiple guilds and only the winning guild of a tournament can unlock the funds (with proof of victory provided by an oracle signature). Then that guild’s contract distributes internally.

Server-wide Events: The game may have events where, say, all players’ mining contributions for a month go into a grand pool, and if a collective goal is met (e.g., defeating a world boss), the pool is unlocked and split among all participants. A contract can hold the pool and only allow spending if provided with a valid signature from the server’s event oracle confirming the boss was defeated. The splitting could be equal shares to all active players or weighted by contribution – again, the transaction that spends from the contract can have multiple outputs to all players. There’s a practical limit (a single BCH transaction can have many outputs; having tens or hundreds of outputs is possible, though size grows – BCH’s larger block size can accommodate it to some extent). Alternatively, the contract could release to the server (with an oracle signature) who then does off-chain distribution; but that reintroduces trust, so we’d prefer the direct on-chain distribution if feasible.

Reward Contracts with CashScript: Based on earlier example, we can create tailored contracts:

  • For a fixed group (like a small guild), hard-code the addresses and enforce equal or proportionate split.
  • For a dynamic group, use an oracle model: the server could generate the list of recipients and encode it somehow for the contract. Since we can’t loop on chain, one approach is to use a Merkle root of the payouts. The contract would then require someone to present a Merkle proof for each payout, but verifying a Merkle proof on BCH script would mean hashing in the script, which is possible for a fixed depth by unrolling but not trivial. Given the complexity, it might be simpler to handle a dynamic set by multiple transactions or multiple contracts.

Non-Custodial Pooled Mining vs P2Pool direct: One might ask, why not have used a Monero pool at the guild level directly? The answer lies in flexibility: Monero can’t do the smart distribution. By switching to BCH for the distribution phase, we leverage BCH’s script to automate the sharing. In effect, the guild or server is acting like a mini-pool operator but encoded as a smart contract rather than a trusted person. This approach also has compliance benefits: even though the server orchestrated the conversion, the final distribution is enforced by code, not by discretion.

Example – Guild Contract Usage:

  1. Guild “Dragons” has 10 members. They decide to pool. The game assigns them a unique contract on BCH, deployed with their 10 addresses and leader’s pubkey.

  2. All mining XMR from those 10 players goes to the server’s XMR address. Every so often, the server swaps XMR→BCH and gets (say) 0.5 BCH. The server then deposits 0.5 BCH into the Dragons guild contract address. Now the contract’s UTXO holds 0.5 BCH under the script control.

  3. When the guild completes a big raid, the server triggers the reward: it sends a message containing a pre-agreed secret “DragonsSlayedTheDragon” to the guild leader in-game. The leader uses a small tool to craft the spending transaction from the contract:

    • Input: the 0.5 BCH UTXO locked by the guild’s CashScript.
    • Outputs: 0.05 BCH to each of 10 member addresses (totalling 0.5 BCH).
    • An unlocking script that includes the leader’s signature and the secret string.
    • This transaction is broadcast to the BCH network.

  4. The BCH miners validate: The script checks leader’s signature (valid) and sha256("DragonsSlayedTheDragon") matches the achievementHash in the contract (it does, assuming the secret was set as that). Then it ensures the outputs exactly match the 10 addresses with 0.05 BCH each, as required. All conditions true, so the transaction is valid and gets confirmed.

  5. Each member receives 0.05 BCH (~some USD equivalent) in their wallets, which they can use or cash out. The on-chain record shows the predetermined split, proving fairness.

In this example, no central party could have stolen the 0.5 BCH at any point – it was locked in the contract, and only the specified conditions released it correctly. If the event never happened, the BCH would remain locked (we might include a fail-safe, like if not distributed by a certain date, maybe allow refund or carry over to next event).

Oracle and Trust: The use of an oracle (the leader or server signing a message) is a point of semi-trust. However, the oracle cannot redirect funds to themselves; at most they could trigger at the wrong time (say lie that event happened). A mitigation is to use a multi-sig or requiring multiple oracles (maybe require signatures from two game masters, or from the leader and a GM). CashScript can handle multiple sigs (e.g., requiring checkMultiSig with M-of-N keys).

User Experience Considerations: Players will need BCH wallets to receive funds. Bitcoin Cash addresses and usage might be new to some, but the game can integrate with a BCH light wallet library or at least instruct users. BCH’s advantage is low fees, so even small outputs like $0.50 can be spent without the fee eating it. If desired, the game could integrate directly such that upon distribution, it also notifies players in-game of their reward and maybe even provides a link to view the transaction on a BCH explorer.

Gas/Fees: On BCH, fees are low (about 1 satoshi/byte normally). A distribution transaction with, say, 10 outputs of 0.05 BCH might be ~400 bytes, costing perhaps 0.000004 BCH fee ($0.000 less than a penny). Even with 100 outputs, it might be a few thousand bytes, still pennies in fees. So cost is negligible, which is a big plus over doing this on Ethereum where that would be cost-prohibitive.

Smart Contract Security: We must ensure the CashScript code is correct. Off-by-one errors in splitting, or forgetting a condition, could lock funds permanently or allow theft. For example, if we didn’t ensure tx.outputs.length == 2 in the earlier example, an attacker could add a third output sending some satoshis to themselves and still satisfy other conditions – thus siphoning dust. Always explicitly check output count and values to avoid that. Testing on BCH testnet is essential before mainnet.

4. Fully Automated, Non-Custodial Workflow from Mining to Distribution

Let’s put it all together into a coherent flow, ensuring that at no point do we rely on custodial trust beyond the minimal necessary (and even that can be mitigated):

Step A: In-Game Mining (Monero, P2Pool) – as previously described. Players perform actions; ServUO triggers hash computations; P2Pool shares are submitted. Now, instead of each player mining to their own address, suppose we set it up such that all mining is done to a single address per reward pool. For example, one address per guild or one for the whole server event. (This is a design choice – we could still do individual then aggregate, but one address simplifies conversion.)

  • The server may actually use one address for all P2Pool mining (meaning all shares credit that address, which is controlled by the server operators for now). While this reintroduces a custodian for the XMR phase, it simplifies conversion. Alternatively, players could receive XMR and voluntarily send it to the pool address for conversion – but expecting that from users is probably too much friction.

  • Non-custodial enhancement: The server’s Monero address used for mining could be a multisig wallet requiring signatures of multiple trusted parties (game admins). This way no single rogue admin can run off with the XMR – it would require collusion, providing some security.

Step B: Monitoring and Conversion Trigger – A background service monitors the Monero wallet’s balance or the P2Pool output. Once enough XMR is accrued (say a threshold of 0.5 XMR, or after a certain time), it initiates the conversion to BCH.

  • If using Atomic Swaps: The service (which could be a script on the server) finds an available swap peer via an API (e.g., calls unstoppableswap.net list of providers). Suppose it finds an offer to trade 0.5 XMR for appropriate BCH. It runs the atomic swap protocol automatically:

    • It prepares a BCH address which is the reward contract address (or a locking script). For atomic swaps, typically the BCH side is the one with an HTLC. But in some protocols, the XMR side can be the one initiating. Let’s assume we do it such that the BCH comes directly to the contract.
    • The swap completes, and 0.5 XMR from the Monero wallet is gone, while an equivalent value (perhaps ~0.5 * price) in BCH minus fees arrives in the contract.

  • If using Haveno: The service has to run a Haveno client node. It posts an offer “sell 0.5 XMR for BCH”. When someone takes it, Haveno will guide through deposit of XMR and BCH in multisig. Once trade completes, BCH is received in the Haveno wallet. We then need to automatically transfer that BCH to the contract. Haveno might not directly support sending to a script address, so likely the BCH lands in a regular address controlled by the server (Haveno’s wallet). Immediately after, an automated step creates a transaction from that wallet into the contract address for the full amount (less any miner fee). We’d script the BCH wallet (using bitcoin-cli or an SPV library) to send to the contract. This introduces a very brief custody of BCH by the server (the moment between trade and deposit to contract). If the server is compromised right then, theoretically funds could be diverted. But this time window is small if automated. To mitigate, the BCH wallet could be multisig too, but Haveno might not support that easily for output.

Step C: Funds Held in BCH Contract – Now the reward money is on the BCH blockchain under the control of a smart contract. This contract was set up in advance with the logic for distribution. Depending on the scenario:

  • If it’s a guild fund, the contract might be specific to that guild’s members.
  • If it’s a global event pool, the contract might be controlled by an oracle (game admin key) and intended to pay many addresses once triggered.

Multiple pools can coexist: e.g., a guild contract per guild, and maybe a global event contract. The server can keep track: XMR mining contributions go to different addresses depending on context (maybe tag each hash event with which pool it should credit). This could be implemented by dedicating different P2Pool addresses or by having players toggle which pool they contribute to. To simplify, perhaps all mining goes to one pool that later gets split as needed (but then you need logic to split by contribution).

Step D: Triggering Distribution – When the time or condition for reward comes:

  • If it’s time-based (say weekly payout), the server can automatically craft the spending transaction at that time, using known data of contributions.
  • If it’s event-based (boss defeated), the server or an authorized player triggers it manually soon after the event.

In either case, an off-chain computation is often needed to determine who gets what. For example, if splitting among 100 players based on contribution, the server calculates each share. It then constructs a transaction with 100 outputs accordingly. The contract likely requires a signature from the server (or some oracle proof) to allow it (because listing 100 addresses on chain in the contract itself is not feasible). So effectively the server acts as an oracle providing the distribution outcome, but the contract enforces that the outcome cannot be different than what was signed off. This can be achieved by the contract verifying the signature and also verifying the outputs match the signed data (this might require encoding the entire output map in a hash that is signed, due to script size limits of checking each output individually).

For instance, the server could produce a hash of the intended payout vector and sign it. The contract could just check the signature and that the hash of the outputs in the spending transaction equals that signed hash. This would require the contract to be able to hash the outputs – BCH doesn’t have a direct “hash all outputs” opcode, but one approach is to supply the hash as part of unlocking arguments and verify it against an expected value in contract (similar to how one would implement an HTLC checking a preimage hash). If the server’s signature is present, we trust the distribution. This is somewhat trusted (the server could sign a wrong distribution, but presumably they wouldn’t cheat their own players; also players can verify if the outputs indeed correspond to what was promised since it’s all on chain).

If more trustlessness is desired, incorporate multiple oracles: e.g., require a known community auditor to co-sign the distribution.

  • The transaction is then broadcast. BCH miners include it, and the contract’s conditions are checked and satisfied, unlocking the UTXO to the specified outputs.

Step E: Players Receive BCH – Each player can then access their BCH reward. They might use a mobile wallet or the game might even integrate a simple BCH wallet for them (for instance, the game could generate an address for each player under the hood using an HD wallet, but that edges into custodial if the game holds keys – better to let players input their own BCH address or seed phrase if they want).

Decentralization and Trust Summary:

  • Mining Phase: Decentralized in terms of pool (P2Pool) but the game server took a role in aggregating. That part was somewhat custodial (if using one address). But because it’s mining (new coins), we’re not taking existing player funds, just distributing newly mined ones, the risk is mainly “could the server keep the mined XMR instead of converting/distributing it?” – which players would notice if promised funds never show. Reputation and the smart contract process provide transparency after conversion (players can see how much BCH went into the contract).
  • Conversion Phase: Non-custodial via atomic swap (no third party holds funds). The server initiates it, but cannot steal the BCH from the atomic swap – either it completes properly or it doesn’t, by design. Using Haveno, the server could technically abort after trade and not forward the BCH to contract, but again that’s a matter of honesty. We can mitigate by having multiple signers in control of that step.
  • Distribution Phase: Non-custodial by smart contract – the rules are enforced on-chain. The only trust is in the oracle triggering event correctly. But even an oracle cannot send funds to the wrong place – the contract won’t allow it; at worst they could withhold triggering (delaying distribution).

Technical Feasibility: This pipeline is technically complex but each part is feasible with today’s tech:

  • Monero P2Pool – proven and running.
  • XMR-BCH atomic swaps – have been demonstrated (XMR-BTC swaps live since 2021, and BCH is similar enough to BTC for the same protocols).
  • CashScript – available and supports covenants needed.
  • Automation – requires some scripting and possibly running multiple blockchain nodes (Monero, BCH full node or light client, Haveno or swap client). It’s an infrastructure challenge but doable for a dedicated server.

Challenges and Considerations in this Pipeline:

  • Conversion Frequency vs. Amount: Converting too often (tiny amounts) would waste fees and time. Too rarely could mean players wait weeks to see BCH. A balance must be struck (maybe do it when a threshold or time elapsed, whichever sooner).
  • Volatility: XMR/BCH price can fluctuate between mining and conversion. If the server accumulates XMR, its value in BCH might change. This could advantage or disadvantage players. It’s essentially currency risk. The game could choose to convert immediately upon each block found to minimize exposure, or just accept the variance.
  • Atomic Swap Availability: There must be counterparties to swap with. If the amounts are small, it might be okay as there could be individuals wanting XMR for BCH. If scale grows, the game might need to split into multiple swaps or find liquidity. Alternatively, the game operators themselves might pre-fund some BCH and act as the counterparty (but that then is more like an in-house exchange and introduces centralization).
  • Tool Maturity: Haveno is still not in full release (as of 2025, it might be close). UnstoppableSwap is active, but the UX might be rough. Running these autonomously requires robust error handling (e.g., if a swap fails or an offer isn’t taken, etc., the system should retry or try a different method).
  • Smart Contract Complexity: Designing the contract for distribution might be the trickiest part. We should thoroughly test the script logic with different scenarios to avoid lockup. For example, what if the guild members change (someone leaves guild) – the contract deployed earlier may have an outdated member list. One solution: use a generic contract that pays to the guild’s multi-sig address instead of individuals, and let the guild handle splitting off-chain. But that reintroduces trust at guild level. Alternatively, only distribute when the member list is final (like at time of payout, not persistent contracts). Perhaps deploy a fresh contract each cycle with the latest list.
  • User Experience: Some players might prefer Monero directly; others might prefer BCH because of easier use (BCH is on normal wallets, etc.). The game could consider giving users a choice: keep your XMR or auto-convert to BCH. But offering choice complicates systems further.
  • Legal: Converting to BCH might have different legal standing (less of a privacy coin, but then you’re engaging in currency exchange even if algorithmically). However, since it’s all user-driven and no fiat, it should be fine, just need to ensure not inadvertently running an exchange business. Doing atomic swaps likely avoids any licensing, as it’s peer-to-peer trades.

To conclude this pipeline: The game acts as a facilitator that mines XMR, trustlessly swaps it to BCH, and uses smart contracts to distribute the value, all with minimal trust. Players benefit from potentially more programmable and group-based rewards (like guild achievements) and the availability of their rewards on a chain with broader ecosystem (they could spend BCH or exchange it further as they like, possibly more easily than Monero in some cases). The game operator benefits from not having custody of player funds at distribution and from the flexibility to craft interesting reward rules enforced by code.

Summary & Conclusion

Integrating Monero’s P2Pool mining into ServUO opens the door to a novel play-to-earn mechanism where gameplay directly drives cryptocurrency mining. The direct integration (Approach 1) leverages Monero’s decentralization and privacy to reward players in XMR without any centralized payout infrastructure, whereas the advanced pipeline (Approach 2) converts those mining rewards into Bitcoin Cash and uses on-chain smart contracts to distribute funds in flexible ways (such as guild-based rewards), all while preserving a non-custodial, decentralized philosophy.

Key takeaways:

  • Technical Feasibility: It is technically feasible to connect a C# game server to Monero’s P2Pool. The server must handle mining job data and RandomX hashing, which can be done via external miners or native libraries. Running a Monero node and P2Pool instance alongside ServUO is required. The integration will need careful multithreading and rate control to maintain game performance.

  • In-Game Triggers: Game events like combat and resource gathering can successfully trigger hash computations. By tuning the frequency and amount of work per trigger, one can balance gameplay impact and mining output. Use asynchronous processing to avoid server lag. This ties player actions to real economic rewards, potentially increasing engagement.

  • Non-Custodial Rewards via P2Pool: P2Pool’s design ensures that payouts go directly to players’ wallet addresses without passing through a game-controlled wallet. This significantly reduces legal/compliance burdens and fosters trust, since the system is provably fair and self-executing (no admin can “hold” or redirect your mining reward). However, P2Pool’s one-address-per-node constraint means scaling to many players may require innovative workarounds or accepting some grouping of rewards.

  • Challenges: The integration is not plug-and-play. Issues include potential performance hits, complexity of handling multiple payout addresses, and the need to secure the system against exploitation. Additionally, players must be educated about how the crypto rewards work. Game design must ensure the crypto layer enhances rather than undermines the core fun of UO.

  • Best Practices: Running P2Pool in mini mode for low hashrate, employing multi-threading and low-priority tasks for mining, and using secure coding patterns are important. We did not find evidence of prior attempts to marry Monero mining with a game server, making this a pioneering effort – inspiration is drawn from analogous cases like websites using in-browser XMR mining for monetization, but here it’s voluntary and gamified. On the BCH side, we take cues from existing Bitcoin Cash smart contract applications like Flipstarter, which demonstrated trustless fundraising via BCH contracts (funds held in escrow and released only when conditions are met). Our use of CashScript covenants for distribution is conceptually similar to these escrow contracts and to AnyHedge style contracts that enforce payout terms.

  • XMR-to-BCH Pipeline: Converting Monero mining rewards into Bitcoin Cash and distributing via smart contracts adds complexity but unlocks new possibilities. Haveno (Bisq fork) provides a private way to trade XMR for BCH using multi-sig escrow, and atomic swap technology offers a trustless conversion with no intermediaries. Bitcoin Cash’s CashScript, despite limitations (no loops, no persistent state), is sufficiently powerful to encode distribution rules such that funds can be split among players without a central custodian. We can design contracts that only execute payouts when given a valid signature or secret (representing a game event success) and that enforce exactly how the outputs must be structured, guaranteeing fairness.

  • Workflow Security: The end-to-end automated workflow ensures that from the moment hashes are computed to the moment BCH is received by players, each step either uses decentralized consensus (mining, on-chain contracts) or multi-party cryptographic protocols (atomic swaps, multisig escrows) to remove single points of failure. The game server’s role is orchestrative: it sets up the conditions and triggers but does not seize custody of the value at any point where it could cheat the system undetected. This maximizes decentralization and aligns with the trustless ethos of cryptocurrencies.

In implementing this, detailed testing and incremental rollout would be wise. A proof-of-concept might start with a single mining address and a simple “admin-triggered payout” to ensure the pieces work. Then one can build out to more granular per-player tracking or the XMR→BCH conversion if the enhanced features are desired. Community feedback from players will also be crucial – some may find the idea of earning crypto exciting, while others might worry it could imbalance the game or attract the wrong crowd. With careful calibration, this system can be a compelling addition to a shard, effectively turning the game’s virtual achievements into tangible crypto rewards in a decentralized manner.

Finally, this integration could serve as a model for other games: it demonstrates how open blockchain systems (like Monero and Bitcoin Cash) can be harnessed to create new reward dynamics without turning the game into a centralized “crypto casino”. Everything is open-source and verifiable – from the Monero mining code to the CashScript contracts – which aligns well with the spirit of Ultima Online’s player-run shards and the open gaming community.

Michael Ten

Michael Ten is an author and artist. He is director of Tenoorja Musubi, and practices Tenqido.