bitcoinschema/sigma

Sigma is a digital signature scheme designed to sign Bitcoin transaction data, enhancing transaction security by incorporating input transaction IDs and output data hashes into the signature process. It addresses replay attack concerns by appending signature fields to custom output scripts, allowing users to assert authorship and integrity of data in blockchain transactions. The protocol supports multiple signing algorithms including BSM (Bitcoin Signed Message) and BRC-77, and is particularly useful for developers building applications that require verifiable transaction data on the Bitcoin SV blockchain.