Messaging: the node

The Messenger runs on Pepecoin testnet, always. This page covers the node side: which binary, how the testnet node is configured next to the mainnet one, the chain rules the message format relies on, and how to get testnet coins. The message format itself is in 02-design.md.

Messaging is testnet-only as a product rule, enforced in code (require_messaging_network() in arcade/config.py refuses any other network). Tokens, NFTs and coins live on mainnet; messages, profiles and the feed live on testnet. One application talks to both nodes.

The format is still designed to mainnet standardness rules, so that it would relay anywhere: testnet sets fRequireStandard = false, and a format that only worked there would be silently unrelayable on a real network.

Pepecoin Core v1.1.0 (released 2024-12-18) is the current release, and the same binaries serve mainnet and testnet. Download and verification are described in ../00-node-setup.md. In short:

Two caveats apply: the signing key expired 2026-01-02 (the signature predates expiry, so it is sound), and trust is single-channel (tarball, checksums, signature and key all come from the same GitHub organisation; the key is not on public keyservers).

Upstream ships builds for every platform the installer supports, so nothing needs to be built from source:

The installer sets up both nodes side by side. Neither touches the other's data.

Both nodes run as your own user because pepecoind always writes .cookie with mode 0600, and no group membership, -rpccookiefile path or POSIX ACL can share a 0600 file across users. Running as the same user as the application makes cookie authentication work with no stored password at all.

The testnet node needs its wallet enabled: it pays message fees.

Check it:

``bash systemctl --user status pepecoind-testnet pepecoin-cli -datadir=$HOME/.pepecoin-testnet getblockchaininfo pepecoin-cli -datadir=$HOME/.pepecoin-testnet getconnectioncount ``

Peers and sync

Both testnet DNS seeds are compiled into the binary (chainparams.cpp), so the node finds peers on its own over port 44874. Expect a small number of peers; testnet is a quiet network. The testnet chain is deeper than its activity suggests (well past 450,000 headers), so a first sync from scratch takes a few hours. Mainnet Pepecoin is a young, low-volume chain and syncs comfortably even on modest hardware.

The index bootstrap the installer downloads (see ../00-node-setup.md) covers the application's own index; the nodes still download and verify blocks themselves.

All checked in the Pepecoin v1.1.0 source (commit 4fb5a0cd):

RPC names differ from modern Bitcoin Core: use signrawtransaction (not …withwallet) and validateaddress (not getaddressinfo). generate, generatetoaddress and fundrawtransaction all exist.

There are three dust thresholds, and the wallet's own floor (DEFAULT_DISCARD_THRESHOLD, 0.01 PEP) is the one that binds when funding through the node; see 02-design.md.

Messages are not squeezed into 80-byte OP_RETURN outputs. The application already has a much larger carrier:

Class B is standard on mainnet, so it is the primary carrier for messages; Class C is used for small records such as key announcements. Consequences:

• A message of up to about 7,500 characters is one transaction, so the 25-transaction unconfirmed-chain limit is not a constraint for ordinary messages.
• Sender binding comes free. Class B's obfuscation keystream is seeded with the sender's address (parsing.cpp:108-131), so a payload only reassembles under the correct sender.
• Obfuscation is not encryption. The keystream derives from a public address, so anyone can strip it. Confidentiality comes entirely from the encryption described in the design.
• Class B costs one marker output plus one dust output per two packets. The multisig outputs include the sender's redeeming pubkey (encoding.cpp:37), so that dust stays spendable by the sender rather than burned.

Every message is a transaction, so the testnet wallet needs coins.

From the arcade's faucet

A new account on an arcade is given a one-time gift of test coins so it can claim its name, post and message straight away. The faucet is testnet-only by default.

By mining

Testnet allows minimum-difficulty blocks, which makes CPU mining practical (pow.cpp:17-28):

``cpp bool AllowMinDifficultyForBlock(...) { if (!params.fPowAllowMinDifficultyBlocks) return false; if (pindexLast->nHeight < 1250) return false; // Allow a minimum-difficulty block if more than 2nTargetSpacing has elapsed return (pblock->GetBlockTime() > pindexLast->GetBlockTime() + params.nPowTargetSpacing2); } ``

So at current heights, if testnet has been quiet for more than 120 seconds (2 × 60 s spacing), the next block may be mined at powLimit (0x00000fff…), roughly 2²⁰ expected Scrypt hashes. On a single CPU core that typically takes a few minutes.

The command-line tool wraps this:

``bash arcade-msg fund ``

It mines one block and stops. One block pays 10,000 PEP, enough for tens of thousands of messages. Coinbase maturity on testnet is 240 blocks, so mined coins become spendable about four hours later; mining more does not shorten that, because maturity is measured in chain height. Start it when you set up your key, not when you first want to send.

Each of these is handled by the installer:

1. RestrictAddressFamilies must include AF_NETLINK, or libzmq aborts at startup. 2. -daemonwait does not exist in this 0.13/0.14-era codebase. Use Type=simple and run in the foreground. 3. The rpcauth HMAC uses the salt as the raw ASCII of the hex string, not decoded hex (httprpc.cpp:118). Getting this wrong yields a silent authentication failure. 4. .cookie is always mode 0600, so cookie auth only works if the client runs as the same user as the daemon. Choose the service user around that. 5. The signing key is expired and not on public keyservers. Fetch it from the source tree at the release tag. 6. Verify before executing: hash and signature, and stop on failure.