Statechains

Statechains are a bitcoin layer 2 design that transfers ownership of a specific unspent transaction output (UTXO) off chain by passing key control from one user to the next, coordinated by a service called a statechain entity. The concept was proposed by developer Ruben Somsen in 2018 and later implemented in projects such as Mercury.

How it works

The coin sits in an on-chain output controlled jointly by the current owner and the statechain entity, each holding a share of the key. To transfer, the entity cooperates with the new owner to establish a fresh key share while the previous owner's share is invalidated, and the new owner receives a pre-signed, timelocked transaction that can withdraw the coin to the chain unilaterally if the entity ever disappears. Because the whole UTXO moves at once, statechains need no channel liquidity and no routing; they suit fixed denominations passed hand to hand. The trade-off is trust: users must rely on the entity to actually delete old key shares and not collude with a past owner.

In the gold vs bitcoin debate

A statechain transfer resembles handing someone a physical coin: the same discrete object changes owners instantly, with no fee per transfer and no ledger entry on the base chain. That makes it one of the more gold-like ways to move bitcoin. The comparison also exposes the trade space of digital money: bitcoin's base layer offers gold-grade bearer finality at a fee, while faster layers like statechains and Lightning accept measured amounts of trust or complexity to gain speed and cost, letting users pick the point on the spectrum that fits each payment.