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use bitcoin::blockdata::script::{Builder, Script};
use bitcoin::blockdata::transaction::TxIn;
use bitcoin::network::constants::Network;
use bitcoin::util::address::Address;
use bitcoin::util::hash::{Hash160, Sha256dHash};
use secp256k1::{self, PublicKey, Secp256k1, SecretKey};
use sign;
use {InputSignature, InputSignatureRef, TxInRef, UnspentTxOutValue};
pub fn address(pk: &PublicKey, network: Network) -> Address {
Address::p2wpkh(pk, network)
}
pub fn script_pubkey(pk: &PublicKey) -> Script {
let witness_version = 0;
let pk_hash = Hash160::from_data(&pk.serialize()[..])[..].to_vec();
Builder::new()
.push_int(witness_version)
.push_slice(&pk_hash)
.into_script()
}
#[derive(Debug)]
pub struct InputSigner {
context: Secp256k1,
public_key: PublicKey,
network: Network,
}
impl InputSigner {
pub fn new(public_key: PublicKey, network: Network) -> InputSigner {
InputSigner {
context: Secp256k1::new(),
public_key,
network,
}
}
pub fn secp256k1_context(&self) -> &Secp256k1 {
&self.context
}
pub fn secp256k1_context_mut(&mut self) -> &mut Secp256k1 {
&mut self.context
}
pub fn signature_hash<'a, 'b, V: Into<UnspentTxOutValue<'b>>>(
&mut self,
txin: TxInRef<'a>,
value: V,
) -> Sha256dHash {
sign::signature_hash(txin, &self.witness_script(), value)
}
pub fn sign_input<'a, 'b, V: Into<UnspentTxOutValue<'b>>>(
&mut self,
txin: TxInRef<'a>,
value: V,
secret_key: &SecretKey,
) -> Result<InputSignature, secp256k1::Error> {
let script = self.witness_script();
sign::sign_input(&mut self.context, txin, &script, value, secret_key)
}
pub fn verify_input<'a, 'b, 'c, V, S>(
&self,
txin: TxInRef<'a>,
value: V,
public_key: &PublicKey,
signature: S,
) -> Result<(), secp256k1::Error>
where
V: Into<UnspentTxOutValue<'b>>,
S: Into<InputSignatureRef<'c>>,
{
sign::verify_input_signature(
&self.context,
txin,
&self.witness_script(),
value,
public_key,
signature.into().content(),
)
}
pub fn spend_input(&self, input: &mut TxIn, signature: InputSignature) {
input.witness = self.witness_data(signature.into());
}
fn witness_data(&self, signature: Vec<u8>) -> Vec<Vec<u8>> {
vec![signature, self.public_key.serialize().to_vec()]
}
fn witness_script(&self) -> Script {
Address::p2pkh(&self.public_key, self.network).script_pubkey()
}
}
#[cfg(test)]
mod tests {
use bitcoin::blockdata::opcodes::All;
use bitcoin::blockdata::script::{Builder, Script};
use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut};
use bitcoin::network::constants::Network;
use rand::{SeedableRng, StdRng};
use TxInRef;
use p2wpk;
use test_data::{btc_tx_from_hex, secp_gen_keypair_with_rng};
#[test]
fn test_native_segwit() {
let mut rng: StdRng = SeedableRng::from_seed([1, 2, 3, 4].as_ref());
let (pk, sk) = secp_gen_keypair_with_rng(&mut rng);
let prev_tx = btc_tx_from_hex(
"02000000000101beccab33bc72bfc81b63fdec8a4a9a4719e4418bdb7b20e47b02074dc42f2d800000000\
017160014f3b1b3819c1290cd5d675c1319dc7d9d98d571bcfeffffff02dceffa0200000000160014368c\
6b7c38f0ff0839bf78d77544da96cb685bf28096980000000000160014284175e336fa10865fb4d1351c9\
e18e730f5d6f90247304402207c893c85d75e2230dde04f5a1e2c83c4f0b7d93213372746eb2227b06826\
0d840220705484b6ec70a8fc0d1f80c3a98079602595351b7a9bca7caddb9a6adb0a3440012103150514f\
05f3e3f40c7b404b16f8a09c2c71bad3ba8da5dd1e411a7069cc080a004b91300",
);
assert_eq!(prev_tx.output[1].script_pubkey, p2wpk::script_pubkey(&pk));
let mut transaction = Transaction {
version: 2,
lock_time: 0,
input: vec![
TxIn {
prev_hash: prev_tx.txid(),
prev_index: 1,
script_sig: Script::default(),
sequence: 0xFFFFFFFF,
witness: Vec::default(),
},
],
output: vec![
TxOut {
value: 0,
script_pubkey: Builder::new()
.push_opcode(All::OP_RETURN)
.push_slice(b"Hello Exonum!")
.into_script(),
},
],
};
let mut signer = p2wpk::InputSigner::new(pk, Network::Testnet);
let signature = signer
.sign_input(TxInRef::new(&transaction, 0), &prev_tx, &sk)
.unwrap();
signer
.verify_input(TxInRef::new(&transaction, 0), &prev_tx, &pk, &signature)
.expect("Signature should be correct");
signer.spend_input(&mut transaction.input[0], signature);
let expected_tx = btc_tx_from_hex(
"0200000000010145f4a039a4bd6cc753ec02a22498b98427c6c288244340fff9d2abb5c63e48390100000\
000ffffffff0100000000000000000f6a0d48656c6c6f2045786f6e756d2102483045022100bdc1be9286\
2281061a14f7153dd57b7b3befa2b98fe85ae5d427d3921fe165ca02202f259a63f965f6d7f0503584b46\
3ce4b67c09b5a2e99c27f236f7a986743a94a0121031cf96b4fef362af7d86ee6c7159fa89485730dac8e\
3090163dd0c282dbc84f2200000000",
);
assert_eq!(transaction, expected_tx);
}
}