sophi 0.2.3

A simple language for non-custodial value swaps

Sophi

A simple language for non-custodial value swaps.

Sophi has no runtime, no blockchain execution, and no custody of funds. You describe the swap. Sophi verifies the math and produces a portable proof.

Install

pip install sophi

Write a swap (from-to)

swap {
  transfer 0.5 BTC from alice to bob
  transfer 50000 USDT from bob to alice
}

Save as trade.sph and run:

sophi compile trade.sph

Before/after still works

swap {
  before:
    alice = 0.5 BTC
    bob = 50000 USDT

  after:
    alice = 50000 USDT
    bob = 0.5 BTC
}

Proof of possession (address + signature)

swap {
  transfer 0.5 BTC from alice to bob
  transfer 50000 USDT from bob to alice

  proof alice:
    address bc1qalice...
    signature H7f8c2d1e4b7...

  proof bob:
    address bc1qbob...
    signature K9d3e1f2a5c8...
}

Proof output

{
  "status": "valid",
  "conservation": {
    "BTC":  { "before": "0.5",   "after": "0.5"   },
    "USDT": { "before": "50000", "after": "50000" }
  },
  "delta": {
    "alice": { "BTC": "-0.5",  "USDT": "+50000" },
    "bob":   { "BTC": "+0.5",  "USDT": "-50000" }
  },
  "before": { "alice": "0.5 BTC",    "bob": "50000 USDT" },
  "after":  { "alice": "50000 USDT", "bob": "0.5 BTC"    },
  "htlc": {
    "secret_hash": "a3f8c2...",
    "timeout_blocks": 144,
    "legs": [
      { "from": "alice", "to": "bob",   "asset": "BTC",  "amount": "0.5"   },
      { "from": "bob",   "to": "alice", "asset": "USDT", "amount": "50000" }
    ]
  }
}

Why it is safe

• Non-custodial by construction
• No on-chain execution
• Conservation per asset
• Delta per participant

License

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