1 //! keysinterface provides keys into rust-lightning and defines some useful enums which describe
2 //! spendable on-chain outputs which the user owns and is responsible for using just as any other
3 //! on-chain output which is theirs.
5 use bitcoin::blockdata::transaction::{OutPoint, TxOut};
6 use bitcoin::blockdata::script::{Script, Builder};
7 use bitcoin::blockdata::opcodes;
8 use bitcoin::network::constants::Network;
9 use bitcoin::util::hash::Hash160;
10 use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
12 use secp256k1::key::{SecretKey, PublicKey};
13 use secp256k1::Secp256k1;
16 use crypto::hkdf::{hkdf_extract,hkdf_expand};
18 use util::sha2::Sha256;
19 use util::logger::Logger;
23 /// When on-chain outputs are created by rust-lightning an event is generated which informs the
24 /// user thereof. This enum describes the format of the output and provides the OutPoint.
25 pub enum SpendableOutputDescriptor {
26 /// Outpoint with an output to a script which was provided via KeysInterface, thus you should
27 /// have stored somewhere how to spend script_pubkey!
28 /// Outputs from a justice tx, claim tx or preimage tx
30 /// The outpoint spendable by user wallet
32 /// The output which is referenced by the given outpoint
35 /// Outpoint commits to a P2WSH, should be spend by the following witness :
36 /// <local_delayedsig> 0 <witnessScript>
37 /// With input nSequence set to_self_delay.
38 /// Outputs from a HTLC-Success/Timeout tx
40 /// Outpoint spendable by user wallet
42 /// local_delayedkey = delayed_payment_basepoint_secret + SHA256(per_commitment_point || delayed_payment_basepoint
43 local_delayedkey: SecretKey,
44 /// witness redeemScript encumbering output
45 witness_script: Script,
46 /// nSequence input must commit to self_delay to satisfy script's OP_CSV
51 /// A trait to describe an object which can get user secrets and key material.
52 pub trait KeysInterface: Send + Sync {
53 /// Get node secret key (aka node_id or network_key)
54 fn get_node_secret(&self) -> SecretKey;
55 /// Get destination redeemScript to encumber static protocol exit points.
56 fn get_destination_script(&self) -> Script;
57 /// Get shutdown_pubkey to use as PublicKey at channel closure
58 fn get_shutdown_pubkey(&self) -> PublicKey;
59 /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
60 /// restarted with some stale data!
61 fn get_channel_keys(&self, inbound: bool) -> ChannelKeys;
64 /// Set of lightning keys needed to operate a channel as described in BOLT 3
66 pub struct ChannelKeys {
67 /// Private key of anchor tx
68 pub funding_key: SecretKey,
69 /// Local secret key for blinded revocation pubkey
70 pub revocation_base_key: SecretKey,
71 /// Local secret key used in commitment tx htlc outputs
72 pub payment_base_key: SecretKey,
73 /// Local secret key used in HTLC tx
74 pub delayed_payment_base_key: SecretKey,
75 /// Local htlc secret key used in commitment tx htlc outputs
76 pub htlc_base_key: SecretKey,
77 /// Local secret key used in justice tx, claim tx and preimage tx outputs
78 pub channel_monitor_claim_key: SecretKey,
80 pub commitment_seed: [u8; 32],
84 /// Generate a set of lightning keys needed to operate a channel by HKDF-expanding a given
85 /// random 32-byte seed
86 pub fn new_from_seed(seed: &[u8; 32]) -> ChannelKeys {
87 let mut prk = [0; 32];
88 hkdf_extract(Sha256::new(), b"rust-lightning key gen salt", seed, &mut prk);
89 let secp_ctx = Secp256k1::without_caps();
91 let mut okm = [0; 32];
92 hkdf_expand(Sha256::new(), &prk, b"rust-lightning funding key info", &mut okm);
93 let funding_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
95 hkdf_expand(Sha256::new(), &prk, b"rust-lightning revocation base key info", &mut okm);
96 let revocation_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
98 hkdf_expand(Sha256::new(), &prk, b"rust-lightning payment base key info", &mut okm);
99 let payment_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
101 hkdf_expand(Sha256::new(), &prk, b"rust-lightning delayed payment base key info", &mut okm);
102 let delayed_payment_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
104 hkdf_expand(Sha256::new(), &prk, b"rust-lightning htlc base key info", &mut okm);
105 let htlc_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
107 hkdf_expand(Sha256::new(), &prk, b"rust-lightning channel monitor claim key info", &mut okm);
108 let channel_monitor_claim_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
110 hkdf_expand(Sha256::new(), &prk, b"rust-lightning local commitment seed info", &mut okm);
113 funding_key: funding_key,
114 revocation_base_key: revocation_base_key,
115 payment_base_key: payment_base_key,
116 delayed_payment_base_key: delayed_payment_base_key,
117 htlc_base_key: htlc_base_key,
118 channel_monitor_claim_key: channel_monitor_claim_key,
124 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
125 /// and derives keys from that.
127 /// Your node_id is seed/0'
128 /// ChannelMonitor closes may use seed/1'
129 /// Cooperative closes may use seed/2'
130 /// The two close keys may be needed to claim on-chain funds!
131 pub struct KeysManager {
132 secp_ctx: Secp256k1<secp256k1::All>,
133 node_secret: SecretKey,
134 destination_script: Script,
135 shutdown_pubkey: PublicKey,
136 channel_master_key: ExtendedPrivKey,
142 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
143 /// RNG is busted) this may panic.
144 pub fn new(seed: &[u8; 32], network: Network, logger: Arc<Logger>) -> KeysManager {
145 let secp_ctx = Secp256k1::new();
146 match ExtendedPrivKey::new_master(&secp_ctx, network.clone(), seed) {
148 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0)).expect("Your RNG is busted").secret_key;
149 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1)) {
150 Ok(destination_key) => {
151 let pubkey_hash160 = Hash160::from_data(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.serialize()[..]);
152 Builder::new().push_opcode(opcodes::All::OP_PUSHBYTES_0)
153 .push_slice(pubkey_hash160.as_bytes())
156 Err(_) => panic!("Your RNG is busted"),
158 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2)) {
159 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key,
160 Err(_) => panic!("Your RNG is busted"),
162 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3)).expect("Your RNG is busted");
173 Err(_) => panic!("Your rng is busted"),
178 impl KeysInterface for KeysManager {
179 fn get_node_secret(&self) -> SecretKey {
180 self.node_secret.clone()
183 fn get_destination_script(&self) -> Script {
184 self.destination_script.clone()
187 fn get_shutdown_pubkey(&self) -> PublicKey {
188 self.shutdown_pubkey.clone()
191 fn get_channel_keys(&self, _inbound: bool) -> ChannelKeys {
192 let channel_pubkey = ExtendedPubKey::from_private(&self.secp_ctx, &self. channel_master_key);
193 let mut seed = [0; 32];
194 for (arr, slice) in seed.iter_mut().zip((&channel_pubkey.public_key.serialize()[0..32]).iter()) {
197 ChannelKeys::new_from_seed(&seed)