CoinCync

Copyright (c) 2025-2026, The CoinCync Project

Privacy money that requires no permission. A fair-launch, RandomX CPU-mined cryptocurrency with mandatory privacy at the consensus layer, an auditable asymptotic supply, and a hash-locked constitution that even its authors cannot quietly change.

Table of Contents

• Development resources
• Vulnerability response
• Research and design
• Announcements
• Introduction
• About this project
• Supporting the project
• License
• Contributing
• Scheduled software/network upgrades
• Release staging schedule and protocol
• Compiling CoinCync from source
  • Dependencies
  • Reproducible builds
• Installing CoinCync from a release
• Running coincync-node
• Running a miner
• Using Tor
• Storage and sync
• Debugging
• Known issues

Development resources

• Web: coincync.network
• Live chain: run a local node and query its JSON-RPC at http://127.0.0.1:28081 (see Run a node). The public api.coincync.network JSON-RPC and explorer.coincync.network endpoints are temporarily unavailable while the front-end hosting is being brought up; connect to the P2P seed 2.29.34.197:28080 and use your own node's RPC in the meantime.
• Discord: join — the primary place for development discussion and coordination
• Security: CyncLabs@proton.me

CoinCync is developed openly. Because it is a small, security-critical project, the Discord #dev channel is the best way to stay current on best practices and in-flight protocol work before integrating against the network — the same reasoning Monero applies to its #monero-dev channel. #dev is about CoinCync protocol development; for help using CoinCync, use the general channels.

Vulnerability response

CoinCync follows a responsible-disclosure process documented in SECURITY.md. Report vulnerabilities privately to CyncLabs@proton.me — please do not open a public issue for a security bug.

The codebase is fuzzed with cargo-fuzz and checked under the Miri interpreter for undefined behavior on suitable pure-Rust components. The disclosure SLA (24-hour first response) is in MAINTAINERS.md.

Research and design

Protocol changes go through the CoinCync Improvement Proposal (CIP) process (see CONTRIBUTING.md). Design documents, threat models, and privacy analyses live under docs/:

• docs/architecture/PRIVACY.md — the privacy model
• docs/PRIVACY_FEATURES.md — per-feature detail with file:line citations
• docs/security/reorg-defense.md — reorg + finality defenses
• docs/cip/ — improvement proposals
• CONSTITUTION.md and docs/BILL_OF_RIGHTS.md — the hash-locked guarantees

Outside researchers are welcome; reach out on Discord #research before duplicating known work.

Announcements

Critical announcements (releases, network upgrades, security advisories) are posted in Discord and attached to GitHub releases. Node and miner operators should watch releases and upgrade when a network upgrade is scheduled.

Introduction

CoinCync is a private, permissionless, fairly launched proof-of-work cryptocurrency. You are your own bank, you control your funds, and your transactions are private by default — no one can trace them unless you choose to disclose.

Privacy. Privacy is mandatory and enforced at the consensus layer, not an opt-in wallet setting. It is built as Concentric Privacy — independent, layered defenses across the transaction, linkability, network, and operational surfaces — so that no single break exposes the whole. CLSAG ring signatures (ring size 16), Bulletproofs+ confidential amounts, stealth addresses, and view tags hide sender, amount, and recipient on-chain.

Security. Every transaction is secured by a distributed proof-of-work consensus network. Wallets are protected by an encrypted seed; a leaked wallet file is useless without the passphrase.

Untraceability. Ring signatures give each spend a set of decoys drawn from an age-matched distribution, so a real spend is statistically indistinguishable from its ring members.

Decentralization. CoinCync mines with RandomX, so validation and mining run on ordinary consumer CPUs — no ASICs, no specialized hardware. Anyone can run the node software, validate the chain, and mine on equal terms.

Constitutional guarantees. The Constitution forbids premine, dev tax, founder allocation, admin authority, surveillance hooks, and external-chain trust — and it is hash-locked into the build, so these guarantees cannot be quietly changed later. Supply approaches an asymptote of 100,000,000 CYNC on an auditable curve; a perpetual 0.6 CYNC/block tail emission continues past it.

About this project

This is the reference implementation of CoinCync, written in Rust. It is open source and free to use under the terms in LICENSE. Anyone may build an alternative implementation that is compatible with the protocol and network.

As with most development projects, the main branch on the repository is the staging area for the latest changes. Changes are developed in feature branches, submitted as pull requests, and reviewed before merging. For production use, prefer a tagged release over main for stability.

Contributions are welcome — see Contributing below.

Supporting the project

CoinCync takes no dev tax, has no premine, and holds no founder allocation — these are constitutional and hash-locked, so there is no insider stake and users are never anyone's exit liquidity. The project is sustained instead by:

• Public-interest grants (e.g. NLnet / NGI0) that fund audits and development.
• Voluntary community crowdfunding on a transparent, per-initiative basis.
• Founders and contributors mining on equal terms, like everyone else.

The most valuable thing you can contribute is not money: run a node, run a miner, review pull requests, or operate an independent seed. A network with many independent operators is worth more than any donation.

License

See LICENSE.

Contributing

If you'd like to help, see CONTRIBUTING.md for guidelines. Small, self-contained fixes can be submitted directly as pull requests to main. Protocol-affecting changes must go through the CIP process. Note that main is protected: all changes land via reviewed pull requests.

Scheduled software/network upgrades

CoinCync uses scheduled hard-fork network upgrades to introduce consensus changes. Operators should run current versions and upgrade before a scheduled upgrade height. Consensus-critical files are protected by a SHA-256 lockfile, so consensus changes are explicit and reviewable.

Dates use YYYY-MM-DD. "Minimum" is the version that follows the new consensus rules. The table below reflects the testnet schedule; the mainnet schedule is finalized before genesis.

Network	Height	Date	Change	Minimum version
Testnet	13,000	—	Hard-fork rules activation	v1.0.12
Testnet	50,000	—	CIP-011 rolling soft-finality (behind rolling-finality)	TBD
Mainnet	genesis	2026-10-01 (target)	Genesis; full ruleset from block 0	TBD

Values marked TBD/— are not finalized as of this revision.

Release staging schedule and protocol

Approximately before a scheduled network upgrade, a release branch is cut from main with the new version tag. Bug-fix PRs target both main and the release branch; large features and optimizations target main only. The release version in Cargo.toml is bumped to match the tag before tagging.

Compiling CoinCync from source

CoinCync is a Rust workspace built with Cargo.

Dependencies

Dependency	Min. version	Purpose
Rust toolchain (rustc + cargo)	1.88.0	build
A C/C++ toolchain (gcc/clang)	any	compiles the RandomX backend
CMake	3.10	RandomX build
Git	any	source checkout

Install the Rust toolchain via rustup, then the platform C toolchain (build-essential cmake on Debian/Ubuntu; base-devel cmake on Arch; gcc gcc-c++ cmake on Fedora; Xcode command-line tools + cmake on macOS).

Clone and build:

# --depth 1 is a shallow clone (latest snapshot only, no history) — much faster
# to download. Drop it if you need the full git history.
git clone --depth 1 https://github.com/ghostrider1092/CoinCync.git coincync
cd coincync
cargo build --release --features randomx

The resulting binaries are in target/release/:

• coincync-node — full node
• coincync-wallet — CLI wallet
• coincync-rig — CPU miner

Run the tests:

cargo test --workspace

RandomX needs ~2 GB of RAM resident for its dataset; allow ~2 GB per parallel build thread when using cargo build -j<N>.

Reproducible builds

Production Linux binaries are produced by a reproducible Docker build so anyone can independently reproduce the release artifacts from a recorded revision. See Dockerfile and the build scripts under scripts/ / deploy/.

Installing CoinCync from a release

Prebuilt Linux x86_64 binaries are attached to each release (node, wallet, and miner). Download, make executable, and place on your PATH:

wget <release-url>/coincync-node
chmod +x coincync-node
./coincync-node --network testnet

Always prefer a tagged release over a source build of main for production use.

Running coincync-node

Run a node on the public testnet (binds 0.0.0.0:28080 P2P, 127.0.0.1:28081 RPC). Default bootstrap uses the DNS seeds seed1/2/3.coincync.network:

./coincync-node --network testnet

Verify it is syncing (from another shell, ~60s later):

curl -s http://127.0.0.1:28081/rpc/testnet \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"get_info"}'
# Expect: peer_count >= 3, height climbing toward the current tip

If DNS is blocked on your network, the binary falls back to the hardcoded seed IP automatically; you can also pass it explicitly:

./coincync-node --network testnet \
  --addnode 2.29.34.197:28080   # public testnet seed (Hetzner, EU)

The current public testnet runs a single stable seed (2.29.34.197:28080), which is also what seed2/seed3.coincync.network resolve to. The older multi-host Vultr fleet (66.135.23.193, 140.82.57.168, 45.32.251.6, 207.148.6.50, 173.199.93.21) was decommissioned on 2026-07-27 — do not --addnode those IPs; they no longer accept connections. Additional independently-operated seeds are tracked in ghostrider1092/CoinCync#148.

--addnode accepts either IP:port or a hostname:port; hostname resolution is refused under --proxy/--tor to avoid a DNS leak.

To run detached, use --detach (and --log-file). List all options with ./coincync-node --help.

Running a miner

The most useful thing you can do for the network is run a miner. Same setup as a node, plus the coincync-rig binary.

Hardware: 4 GB RAM minimum (RandomX dataset needs ~2 GB resident), 2 CPU cores recommended. A $5–10/mo VPS or a spare home machine works.

# 1. Generate a payout wallet
./coincync-wallet --wallet ~/.coincync/wallets/miner.wallet create --password YOUR_PASSWORD
./coincync-wallet --wallet ~/.coincync/wallets/miner.wallet address --password YOUR_PASSWORD
# Save the tCYNC... (testnet) address — block rewards land there.

# 2. Point the rig at your local node + payout address
./coincync-rig run-solo \
  --node http://127.0.0.1:28081 \
  --address tCYNC_YOUR_ADDRESS_HERE \
  --threads 0   # 0 = auto-detect CPU count

coincync-rig logs BLOCK FOUND, submitting when it solves a block. Say hi in Discord #mining once you're up so operators can prioritize your node.

The rig requires at least 3 connected peers before it will mine. This is a deliberate anti-fork guard: a node that mines while isolated (or barely connected) risks extending a minority fork that the network later reorgs away, wasting the work. If the rig logs that it is waiting for peers, check your node's peer_count with the get_info call above and confirm outbound port 28080 is not firewalled. With only one public seed today, a seed outage can leave new nodes unable to reach the 3-peer floor until it recovers (see ghostrider1092/CoinCync#148).

Using Tor

CoinCync supports routing peer-to-peer traffic over a SOCKS proxy / Tor. Start the node with --proxy <ip:port> (and --tor for onion routing). Under a proxy, --addnode will not perform plaintext DNS resolution, and the node avoids leaking your interest in specific peers or transactions. See the network privacy docs for the full Dandelion++ + Noise-XX + cover-traffic model.

Storage and sync

CoinCync is a young chain, so full history is small. Fresh nodes sync from the seeds and cross-check node-local rolling checkpoints for long-range-attack defense; the hardcoded consensus-checkpoint table is populated post-launch (currently empty). Light-wallet sync downloads compact block digests and scans locally, so the node never answers "does this specific output exist" — a surveillance- resistance property (there is deliberately no balance-lookup RPC).

Debugging

First, ensure you are running the latest build from the repository.

• Set RUST_BACKTRACE=1 (or full) for a backtrace on panic.
• Increase log verbosity with --log-level / RUST_LOG.
• For a running systemd service, inspect logs with journalctl -u coincync-node.
• For crashes, run under gdb --args ./coincync-node ... and bt, or enable core dumps with ulimit -c unlimited.
• Build with debug assertions for extra checks: cargo build (debug profile).

Known issues

CoinCync is early-stage infrastructure software on public testnet. Honest current state:

• Single-miner network. Today most testnet hashrate is on one operator's box; every maintenance restart produces a visible chain stall. This is the biggest pre-mainnet issue and the reason we actively recruit community miners.
• Provider concentration. Fleet nodes are hosted across regions of a single cloud provider; we mitigate by inviting independent operators on other providers.
• Phase-2 modules feature-gated. Shielded modules (Orchard / Lelantus Spark / MimbleWimble kernels) and rolling soft-finality ship behind feature flags, off by default until a future activation.
• Atomic swaps in progress. CYNC↔BTC atomic-swap machinery is shipped; the real adaptor-signature crypto is pending its audit window.
• Wallet UX is mid-refactor; some flows are still utilitarian.

Use at your own risk. Testnet coins have no value; mainnet is not yet live.