sophi 0.1.5

Balance-based non-custodial swap language for Bitcoin

Sophi

Balance-based non-custodial swap language for Bitcoin.

Sophi is a language with one primitive: the balance. When both sides are equal, a non-custodial atomic swap executes on Bitcoin. No escrow. No intermediary. No custodian.

Install

pip install sophi

Write a swap

swap {
  alice wants  0.5 BTC
  alice gives  50000 USDT

  bob wants    50000 USDT
  bob gives    0.5 BTC
}

Save as trade.sph and run:

sophi compile trade.sph

Blind swap (private values)

swap {
  alice wants  blind(a3f8c2d1e4b7a9f0c2d1e4b7a9f0c2d1e4b7a9f0c2d1e4b7a9f0c2d1e4b7a9f0)
  alice gives  blind(b1e2d3c4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2)

  bob wants    blind(b1e2d3c4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2)
  bob gives    blind(a3f8c2d1e4b7a9f0c2d1e4b7a9f0c2d1e4b7a9f0c2d1e4b7a9f0c2d1e4b7a9f0)
}

Nobody sees the amounts until settlement. This is the foundation of OTC dark pool privacy.

How it works

• wants — what a party wants to receive
• gives — what a party is offering
• blind(hash) — hides the value using SHA-256 commitment
• partial — accepts partial fill
• expires block(N) — swap expires at Bitcoin block N

The compiler checks that all balances are in equilibrium before generating anything. If alice gives does not equal bob wants, you get a clear error — not a runtime failure on a live network.

Multi-party

swap {
  alice wants  blind(H1)
  alice gives  blind(H2)

  bob wants    blind(H2)
  bob gives    blind(H3)

  carol wants  blind(H3)
  carol gives  blind(H1)
}

Up to 8 parties. All legs settle atomically.

Non-custodial by construction

Sophi has no syntax for depositing funds into a contract. The only thing you can express is a condition for transfer. Custodial code is not forbidden — it is unwritable.

License

Business Source License 1.1 — converts to Apache 2.0 after 4 years.