The Main Chain: ELA
What It Is
The ELA main chain is the foundation of the Elastos ecosystem: a shared ledger for ELA transfers, governance, validator registration, council operations, and cross-chain events. The reference implementation is written in Go (elastos/Elastos.ELA) and the network has been running since December 2017.
The main chain is deliberately not a general-purpose smart-contract platform. It anchors security and governance; execution layers live on sidechains (ESC and EID).
At a Glance
| Fact | Detail |
|---|---|
| Launched | December 2017 |
| Consensus | AuxPoW (merged mining with Bitcoin) + BPoS |
| Sidechain consensus | PBFT with the same BPoS validator set |
| Block interval | ~2 minutes |
| Block finality | Instant (BPoS + PBFT) |
| Validator count | ~70 elected + 12 Elastos Council; see nodes.elastos.net |
| Block reward split | 35% miners, 35% validators and voters, 30% Elastos DAO treasury |
| Sidechains | ESC (Chain ID 20, smart contracts) and EID (Chain ID 22, identity) |
| Identity standard | W3C DID (Decentralized Identifiers) |
Accounts, Keys, and the UTXO Model
The main chain uses a UTXO model (like Bitcoin): transactions spend previous outputs and create new ones, rather than editing a single account balance.
Signatures use the P-256 curve (secp256r1). This is not Bitcoin's secp256k1 — wallets and integrations must use the correct curve and address formats. See Dual-Curve Architecture for details.
The node recognizes 40+ transaction types, including:
| Type | Hex | Use |
|---|---|---|
| TransferAsset | 0x02 | Simple ELA transfers |
| TransferCrossChainAsset | 0x08 | Lock ELA for a sidechain deposit |
| RegisterProducer | 0x09 | Register or update a BPoS validator |
| CRCProposal | 0x25 | Elastos DAO proposals and governance |
When you see unusual transactions on a block explorer, the transaction type tells you whether it is a payment, a vote, a cross-chain move, or a governance action.
How It Stays Secure: Merged Mining and BPoS
Merged mining (AuxPoW): Bitcoin miners can merge-mine ELA without extra computation. Elastos uses AuxPoW with Bitcoin (chain ID 1224). Security inherits from Bitcoin's hash rate — the largest proof-of-work network in the world.
BPoS validators: The active set is elected through bonded staking — typically ~70 publicly elected validators plus 12 Elastos Council nodes (see nodes.elastos.net). Consensus requires a two-thirds supermajority. A backup candidate pool ensures liveness when active producers drop.
Validators can be penalized after approximately two days of inactivity (MaxInactiveRounds: 1,440 rounds). BPoS activated at block height 1,405,000 (April 2023).
If the entire validator set is unavailable for 12 hours, the network falls back to pure proof-of-work — a built-in degradation mode.
Network and Ports
Anyone can run a full node. Typical requirements:
| Resource | Expectation |
|---|---|
| Disk | ~200 GB (grows over time) |
| RAM | ~16 GB |
| Binary | Single Go build, ~70 MB |
Default ports:
| Port | Role |
|---|---|
| 20338 | P2P peer protocol |
| 20336 | JSON-RPC |
| 20334 | REST API |
Do not expose RPC/REST to the internet without authentication. Run nodes with proper access controls.
Governance Heights
Network upgrades activate at fixed block heights. Key examples:
| Height parameter | Meaning |
|---|---|
| VoteStartHeight | On-chain voting mechanics activate |
| HalvingRewardHeight | First halving of block rewards (1,051,200) |
| DPoSV2StartHeight | BPoS staking consensus activates (1,405,000) |
| SchnorrStartHeight | Schnorr aggregate signing for cross-chain multi-sig |
Each software version's config.json lists all activation heights. Always run a current node version before mandatory heights.
What the Main Chain Does Not Do
The main chain does not host general smart contracts. That restraint shrinks the attack surface: asset and governance logic stay in well-audited UTXO scripts and predefined transaction types, while ESC handles programmable execution.
Who Runs It
You can. The software is open source. Miners, exchanges, wallets, and analysts run nodes for their own needs. Validators stake and campaign for votes. Users hold ELA and participate in governance. Together they enforce one canonical history, without a single operator owning the chain.
Miners (via Bitcoin pools) collect the 35% PoW slice. Validators and voters (pledged stake) collect the 35% BPoS slice. Elastos DAO spends the 30% treasury through proposals.