// Miniscript // Written in 2019 by // Andrew Poelstra // // To the extent possible under law, the author(s) have dedicated all // copyright and related and neighboring rights to this software to // the public domain worldwide. This software is distributed without // any warranty. // // You should have received a copy of the CC0 Public Domain Dedication // along with this software. // If not, see . // //! Example: Verifying a signed transaction extern crate bitcoin; extern crate sapio_miniscript as miniscript; use bitcoin::consensus::Decodable; use bitcoin::hashes::Hash; use bitcoin::util::sighash; use bitcoin::{secp256k1, TxOut}; // secp256k1 re-exported from rust-bitcoin use miniscript::interpreter::KeySigPair; use std::str::FromStr; fn main() { // tx `f27eba163c38ad3f34971198687a3f1882b7ec818599ffe469a8440d82261c98` #[cfg_attr(feature="cargo-fmt", rustfmt_skip)] let tx_bytes = vec![ 0x01, 0x00, 0x00, 0x00, 0x02, 0xc5, 0x11, 0x1d, 0xb7, 0x93, 0x50, 0xc1, 0x70, 0x28, 0x41, 0x39, 0xe8, 0xe3, 0x4e, 0xb0, 0xed, 0xba, 0x64, 0x7b, 0x6c, 0x88, 0x7e, 0x9f, 0x92, 0x8f, 0xfd, 0x9b, 0x5c, 0x4a, 0x4b, 0x52, 0xd0, 0x01, 0x00, 0x00, 0x00, 0xda, 0x00, 0x47, 0x30, 0x44, 0x02, 0x20, 0x1c, 0xcc, 0x1b, 0xe9, 0xaf, 0x73, 0x4a, 0x10, 0x9f, 0x66, 0xfb, 0xed, 0xeb, 0x77, 0xb7, 0xa1, 0xf4, 0xb3, 0xc5, 0xff, 0x3d, 0x7f, 0x46, 0xf6, 0xde, 0x50, 0x69, 0xbb, 0x52, 0x7f, 0x26, 0x9d, 0x02, 0x20, 0x75, 0x37, 0x2f, 0x6b, 0xd7, 0x0c, 0xf6, 0x45, 0x7a, 0xc7, 0x0e, 0x82, 0x6f, 0xc6, 0xa7, 0x5b, 0xf7, 0xcf, 0x10, 0x8c, 0x92, 0xea, 0xcf, 0xfc, 0xb5, 0xd9, 0xfd, 0x77, 0x66, 0xa3, 0x58, 0xa9, 0x01, 0x48, 0x30, 0x45, 0x02, 0x21, 0x00, 0xfe, 0x82, 0x5b, 0xe1, 0xd5, 0xfd, 0x71, 0x67, 0x83, 0xf4, 0x55, 0xef, 0xe6, 0x6d, 0x61, 0x58, 0xff, 0xf8, 0xc3, 0x2b, 0x93, 0x1c, 0x5f, 0x3f, 0xf9, 0x8e, 0x06, 0x65, 0xa9, 0xfd, 0x8e, 0x64, 0x02, 0x20, 0x22, 0x01, 0x0f, 0xdb, 0x53, 0x8d, 0x0f, 0xa6, 0x8b, 0xd7, 0xf5, 0x20, 0x5d, 0xc1, 0xdf, 0xa6, 0xc4, 0x28, 0x1b, 0x7b, 0xb7, 0x6f, 0xc2, 0x53, 0xf7, 0x51, 0x4d, 0x83, 0x48, 0x52, 0x5f, 0x0d, 0x01, 0x47, 0x52, 0x21, 0x03, 0xd0, 0xbf, 0x26, 0x7c, 0x93, 0x78, 0xb3, 0x18, 0xb5, 0x80, 0xc2, 0x10, 0xa6, 0x78, 0xc4, 0xbb, 0x60, 0xd8, 0x44, 0x8b, 0x52, 0x0d, 0x21, 0x25, 0xa1, 0xbd, 0x37, 0x2b, 0x23, 0xae, 0xa6, 0x49, 0x21, 0x02, 0x11, 0xa8, 0x2a, 0xa6, 0x94, 0x63, 0x99, 0x0a, 0x6c, 0xdd, 0x48, 0x36, 0x76, 0x36, 0x6a, 0x44, 0xac, 0x3c, 0x98, 0xe7, 0x68, 0x54, 0x69, 0x84, 0x0b, 0xf2, 0x7a, 0x72, 0x4e, 0x40, 0x5a, 0x7e, 0x52, 0xae, 0xfd, 0xff, 0xff, 0xff, 0xea, 0x51, 0x1f, 0x33, 0x7a, 0xf5, 0x72, 0xbb, 0xad, 0xcd, 0x2e, 0x03, 0x07, 0x71, 0x62, 0x3a, 0x60, 0xcc, 0x71, 0x82, 0xad, 0x74, 0x53, 0x3e, 0xa3, 0x2f, 0xc8, 0xaa, 0x47, 0xd2, 0x0e, 0x71, 0x01, 0x00, 0x00, 0x00, 0xda, 0x00, 0x48, 0x30, 0x45, 0x02, 0x21, 0x00, 0xfa, 0x2b, 0xfb, 0x4d, 0x49, 0xb7, 0x6d, 0x9f, 0xb4, 0xc6, 0x9c, 0xc7, 0x8c, 0x36, 0xd2, 0x66, 0x92, 0x40, 0xe4, 0x57, 0x14, 0xc7, 0x19, 0x06, 0x85, 0xf7, 0xe5, 0x13, 0x94, 0xac, 0x4e, 0x37, 0x02, 0x20, 0x04, 0x95, 0x2c, 0xf7, 0x75, 0x1c, 0x45, 0x9d, 0x8a, 0x8b, 0x64, 0x76, 0x76, 0xce, 0x86, 0xf3, 0xbd, 0x69, 0xff, 0x39, 0x17, 0xcb, 0x99, 0x85, 0x14, 0xbd, 0x73, 0xb7, 0xfc, 0x04, 0xf6, 0x4c, 0x01, 0x47, 0x30, 0x44, 0x02, 0x20, 0x31, 0xae, 0x81, 0x1e, 0x35, 0x7e, 0x80, 0x00, 0x01, 0xc7, 0x57, 0x27, 0x7a, 0x22, 0x44, 0xa7, 0x2b, 0xd5, 0x9d, 0x0a, 0x00, 0xbe, 0xde, 0x49, 0x0a, 0x96, 0x12, 0x3e, 0x54, 0xce, 0x03, 0x4c, 0x02, 0x20, 0x05, 0xa2, 0x9f, 0x14, 0x30, 0x1e, 0x5e, 0x2f, 0xdc, 0x7c, 0xee, 0x49, 0x43, 0xec, 0x78, 0x78, 0xdf, 0x73, 0xde, 0x96, 0x27, 0x00, 0xa4, 0xd9, 0x43, 0x6b, 0xce, 0x24, 0xd6, 0xc3, 0xa3, 0x57, 0x01, 0x47, 0x52, 0x21, 0x03, 0x4e, 0x74, 0xde, 0x0b, 0x84, 0x3f, 0xaa, 0x60, 0x44, 0x3d, 0xf4, 0x76, 0xf1, 0xf6, 0x14, 0x4a, 0x5b, 0x0e, 0x76, 0x49, 0x9e, 0x8a, 0x26, 0x71, 0x07, 0x36, 0x5b, 0x32, 0xfa, 0xd5, 0xd0, 0xfd, 0x21, 0x03, 0xb4, 0xa6, 0x82, 0xc8, 0x6a, 0xd9, 0x06, 0x38, 0x8f, 0x99, 0x52, 0x76, 0xf0, 0x84, 0x92, 0x72, 0x3a, 0x8c, 0x5f, 0x32, 0x3c, 0x6a, 0xf6, 0x92, 0x97, 0x17, 0x40, 0x5d, 0x2e, 0x1b, 0x2f, 0x70, 0x52, 0xae, 0xfd, 0xff, 0xff, 0xff, 0x02, 0xa7, 0x32, 0x75, 0x01, 0x00, 0x00, 0x00, 0x00, 0x19, 0x76, 0xa9, 0x14, 0xfb, 0xf7, 0x76, 0xff, 0xeb, 0x3b, 0xb8, 0x89, 0xb2, 0x01, 0xa5, 0x3f, 0x5f, 0xb0, 0x55, 0x4f, 0x6e, 0x6f, 0xa2, 0x56, 0x88, 0xac, 0x19, 0x88, 0x56, 0x01, 0x00, 0x00, 0x00, 0x00, 0x17, 0xa9, 0x14, 0xd3, 0xb6, 0x1d, 0x34, 0xf6, 0x33, 0x7c, 0xd7, 0xc0, 0x28, 0xb7, 0x90, 0xb0, 0xcf, 0x43, 0xe0, 0x27, 0xd9, 0x1d, 0xe7, 0x87, 0x09, 0x5d, 0x07, 0x00, ]; let transaction = bitcoin::Transaction::consensus_decode(&mut &tx_bytes[..]).expect("decode transaction"); let spk_input_1 = bitcoin::Script::from(vec![ 0xa9, 0x14, 0x92, 0x09, 0xa8, 0xf9, 0x0c, 0x58, 0x4b, 0xb5, 0x97, 0x4d, 0x58, 0x68, 0x72, 0x49, 0xe5, 0x32, 0xde, 0x59, 0xf4, 0xbc, 0x87, ]); let interpreter = miniscript::Interpreter::from_txdata( &spk_input_1, &transaction.input[0].script_sig, &transaction.input[0].witness, 0, 0, // TODO: Replace with actual hash bitcoin::hashes::sha256::Hash::from_inner([0u8; 32]), ) .unwrap(); let desc_string = interpreter.inferred_descriptor_string(); println!("Descriptor: {}", desc_string); miniscript::Descriptor::::from_str(&desc_string) .expect("this descriptor can be reparsed with sanity checks passing"); interpreter .inferred_descriptor() .expect("we can use this method to do the above from_str for us"); // 1. Example one: learn which keys were used, not bothering // to verify the signatures (trusting that if they're on // the blockchain, standardness would've required they be // either valid or 0-length. println!("\nExample one"); for elem in interpreter.iter_assume_sigs() { // Don't bother checking signatures match elem.expect("no evaluation error") { miniscript::interpreter::SatisfiedConstraint::PublicKey { key_sig } => { // Check that the signature is ecdsa sig let (key, sig) = key_sig .as_ecdsa() .expect("Expected Ecdsa sig, found schnorr sig"); println!("Signed with {}: {}", key, sig); } _ => {} } } // 2. Example two: verify the signatures to ensure that invalid // signatures are not treated as having participated in the script let secp = secp256k1::Secp256k1::new(); // Sometimes it is necessary to have additional information to get the bitcoin::PublicKey // from the MiniscriptKey which can supplied by `to_pk_ctx` parameter. For example, // when calculating the script pubkey of a descriptor with xpubs, the secp context and // child information maybe required. let interpreter = miniscript::Interpreter::from_txdata( &spk_input_1, &transaction.input[0].script_sig, &transaction.input[0].witness, 0, 0, bitcoin::hashes::sha256::Hash::from_inner([0u8; 32]), ) .unwrap(); // We can set prevouts to be empty list because this is a legacy transaction // and this information is not required for sighash computation. let prevouts = sighash::Prevouts::All::(&[]); println!("\nExample two"); for elem in interpreter.iter(&secp, &transaction, 0, &prevouts) { match elem.expect("no evaluation error") { miniscript::interpreter::SatisfiedConstraint::PublicKey { key_sig } => { let (key, sig) = key_sig.as_ecdsa().unwrap(); println!("Signed with {}: {}", key, sig); } _ => {} } } // 3. Example three: same, but with the wrong signature hash, to demonstrate // what happens given an apparently invalid script let secp = secp256k1::Secp256k1::new(); let message = secp256k1::Message::from_slice(&[0x01; 32][..]).expect("32-byte hash"); let interpreter = miniscript::Interpreter::from_txdata( &spk_input_1, &transaction.input[0].script_sig, &transaction.input[0].witness, 0, 0, bitcoin::hashes::sha256::Hash::from_inner([0u8; 32]), ) .unwrap(); let iter = interpreter.iter_custom(Box::new(|key_sig: &KeySigPair| { let (pk, ecdsa_sig) = key_sig.as_ecdsa().expect("Ecdsa Sig"); ecdsa_sig.hash_ty == bitcoin::EcdsaSighashType::All && secp .verify_ecdsa(&message, &ecdsa_sig.sig, &pk.inner) .is_ok() })); println!("\nExample three"); for elem in iter { let error = elem.expect_err("evaluation error"); println!("Evaluation error: {}", error); } }