bitcoin-dev

Signing a Bitcoin Transaction with Lamport Signatures (no changes needed)

Signing a Bitcoin Transaction with Lamport Signatures (no changes needed)

Original Postby Ben Carman

Posted on: May 9, 2024 00:31 UTC

In a recent exchange between Ethan Heilman and David A.

Harding, an innovative approach was proposed to navigate the constraints posed by the 201 opcode limit in tapscript, potentially opening new avenues for the implementation of covenants in Bitcoin's scripting language. The conversation shed light on a technique that leverages the OP_SIZE of a signature to make conditional verifications based on the binary value represented by a particular bit—essentially verifying a '0' or '1' condition without breaching resource limits previously mitigated through taproot's introduction.

The discussion highlighted the possibility of employing schnorr signatures to implement this method, where the presence or absence of the SIGHASH_ALL flag would correspond to the binary conditions. This clever utilization of signature characteristics aims to circumvent the opcode limitations without compromising security, as the nature of the signature inherently commits to the specific sighash type used, be it SIGHASH_DEFAULT or SIGHASH_ALL.

While this technique presents a novel workaround to existing constraints, its applicability might be initially limited to operations involving a single bit of information within tapscript. The dialogue between the two programmers underlines an ongoing exploration into how Bitcoin's scripting capabilities can be expanded, reflecting a broader interest in enhancing the flexibility and functionality of smart contract provisions on the platform.