Building Ergo: Lite full nodes

Ergo allows any user to run a full node with low resources – meaning you can help maintain the network with a device as simple as a Raspberry Pi.

In a previous post, we looked at Ergo’s SPV mode, which allows for secure, efficient mobile clients. This enables users to make transactions using almost any device.

At the other end of the scale, you might want to run a full node. If you’re a miner, this will require that you download the full blockchain, because you’ll need the whole UTXO (unspent outputs) set to mine new blocks. But you can still run a full node without that UTXO set – vastly reducing the specification and expense of the hardware needed.

Ergo blocks

In Ergo, just like Bitcoin, Ethereum and other blockchains, blocks are broken into sections. In Bitcoin, there’s simply a block header and the transactions themselves. But in Ergo, we have some extra sections that enable new functionality:

• Header
• Transactions
• Extensions
• Proofs of UTXO transformation

The ‘extension’ section contains certain mandatory fields (including links for NiPoPoW, once per 1,024 block epoch) and parameters for miner voting, such as current block size. It can also contain arbitrary fields.

What this means in practice is that different types of node and client can download only those sections of the blocks they need – reducing the demands for storage, bandwidth and CPU cycles.

Lite full nodes

While miners need to download everything, lite full nodes only need the transactions and proofs. This means they have a cryptographic guarantee of transactions, without holding the full UTXO set itself.

Lite full nodes check the proofs generated by full nodes (including miners) who do hold the full blockchain, providing a guarantee of ledger validity. In Ethereum, these nodes are called Stateless Clients.

For Ergo, it means you can run a full node and maintain the network with a device as simple as a Raspberry Pi with 512 MB RAM. This provides the ideal balance between ensuring the security of the network and placing an unnecessary burden on users who wish to do so – improving decentralisation and democratising participation in the Ergo network and community.