An overview of the OP_PUSH_TX technique, its internal implementation, and the smart contract applications it enables, including a live demo.
The OP_PUSH_TX technique allows a smart contract to access the current transaction's data by pushing it onto the stack.
The technique pushes the SIGHASH pre-image, which contains transaction data like inputs and outputs, onto the stack for inspection.
The technique is implemented as a pseudo-opcode using existing script commands to verify the SIGHASH pre-image is for the current transaction.
By inspecting the transaction pre-image, smart contracts can enforce rules on future outputs, replicating features like CLTV and P2SH.
Stateful smart contracts are created by dividing the locking script into immutable code and mutable data, ensuring state transitions correctly in subsequent transactions.
The ability to maintain state enables complex applications like fully on-chain games, fungible and non-fungible tokens, and financial instruments.
A live demo shows a Tic-Tac-Toe game where each move is a Bitcoin transaction, enforcing game rules on-chain and preventing cheating.
A recap of the OP_PUSH_TX technique and its applications, with links to sCrypt's open-source code, documentation, and community channels.
33:37Jack Davies & Alessio Pagani
47:45Liu Xiaohui
37:28Matej Trampuš & Steve Shadders
1:06:12Steve Shadders
42:32Glenn Wolfe
42:37Rafa Jiménez
41:09Evan Freeman
46:29Joshua Henslee
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Jobs that call for the skills explored in this talk.
SMG Swiss Marketplace Group
Ho Chi Minh City, Viet Nam