How it works
A short guide to the app — what each tab does and which concepts it uses. Back to the main EuroJackCoin page: here.
🔑 Public key and balance (Overview tab)
On first launch, the app automatically generates your wallet — a pair of cryptographic keys (Ed25519). The public key is your "account number" — you can safely share it with anyone who wants to send you coins. The other half of the pair (the private key) is never shown to anyone — it's used to sign your transactions.
Your balance isn't stored anywhere directly — it's recalculated from scratch each time, based on the entire transaction history in the blockchain.
⛏️ Mining
"Mining" means appending a new block to the chain. Whoever mines a block gets an EJC reward for it — just like in real Bitcoin. There are two modes:
- Mine block — mines a single block and stops.
- Mine in loop — mines blocks one after another, non-stop, until you click "Stop mining".
💸 Sending (Send tab)
You enter the recipient's public key and the amount. If the recipient is already a known node on the network, you can pick them from the Known recipient list instead of pasting the key manually. The transaction goes into a new block (together with your reward for mining it) and is broadcast to known nodes on the network.
📥 Received
A list of transactions in which you were the recipient.
🔗 Chain
The full history of all mined blocks — each block points to the previous one, so reverting or swapping anything inside it immediately breaks the whole chain from that point on (which is why blockchain is hard to falsify).
🌐 Network (Network tab)
This is where all the peer-to-peer network magic happens:
- Listen — starts your node so others can connect to you.
- Known nodes — the list of computers your app already knows (on the same local network — automatically; outside of it — you need to add them manually by IP address).
- Seeds — fixed, trusted starting points. Adding just ONE seed is enough to learn about the rest of the network it already knows (exactly how "DNS seeds" work in real Bitcoin).
- Broadcast now — manually sends your chain to all known nodes, in case the automatic mechanism missed something.
The network's rule: the longest valid chain wins — exactly like in Bitcoin. With one extra safeguard built into this app: a new chain will NEVER be accepted if it would decrease your own balance — so your mined/received coins are safe.
📡 How to set up the network
On the same local network (same WiFi/router) — nothing to do. Just click "Listen" on both computers, and the app will find the other one automatically.
Outside the local network (different home, different internet) — automatic discovery does NOT work (a physical limitation of this technology, not a setting to turn on). You need to:
- Find out the public IP address of that network — on that computer, just Google "what is my ip address". A local address from
ipconfig(e.g. 192.168.x.x) is not enough — that number repeats in every home in the world. - Set up port forwarding on that network's router (Port Forwarding / Virtual Server / NAT) — the port the app listens on (1700 by default), pointed to that specific computer's local address.
- Give that computer a fixed local address in the router, so the forwarding doesn't break after the address changes.
- Only now can the other user add that public address as a Seed (Network tab) and use it to reach the rest of the network through it.
Alternative without port forwarding: ZeroTier or Hamachi on both computers — they create a shared virtual network, which works like being on the same WiFi, with no router configuration needed.