50 lines
1.4 KiB
Go
50 lines
1.4 KiB
Go
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package main
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import (
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"fmt"
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"github.com/lightningnetwork/lnd/lnwallet"
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"github.com/roasbeef/btcd/btcec"
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"github.com/roasbeef/btcd/chaincfg/chainhash"
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)
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// nodeSigner is an implementation of the MessageSigner interface backed by the
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// identity private key of running lnd node.
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type nodeSigner struct {
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privKey *btcec.PrivateKey
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}
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// newNodeSigner creates a new instance of the nodeSigner backed by the target
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// private key.
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func newNodeSigner(key *btcec.PrivateKey) *nodeSigner {
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return &nodeSigner{
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privKey: key,
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}
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}
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// SignMessage signs a double-sha256 digest of the passed msg under the
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// resident node private key. If the target public key is _not_ the node's
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// private key, then an error will be returned.
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func (n *nodeSigner) SignMessage(pubKey *btcec.PublicKey,
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msg []byte) (*btcec.Signature, error) {
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// If this isn't our identity public key, then we'll exit early with an
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// error as we can't sign with this key.
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if !pubKey.IsEqual(n.privKey.PubKey()) {
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return nil, fmt.Errorf("unknown public key")
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}
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// Otherwise, we'll sign the dsha256 of the target message.
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digest := chainhash.DoubleHashB(msg)
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sign, err := n.privKey.Sign(digest)
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if err != nil {
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return nil, fmt.Errorf("can't sign the message: %v", err)
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}
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return sign, nil
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}
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// A compile time check to ensure that nodeSigner implements the MessageSigner
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// interface.
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var _ lnwallet.MessageSigner = (*nodeSigner)(nil)
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