bb84f0ebc8
This commit adds a RevocationKeyLocator field to the OpenChannel struct so that the SCB derivation doesn't have to brute-force the sha chain root key and match the public key. ECDH derivation is now used to derive the key instead of regular private key derivation a la DerivePrivKey. The legacy can still be used to recover old channels.
52 lines
1.5 KiB
Go
52 lines
1.5 KiB
Go
// +build !rpctest
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package lnwallet
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import (
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"github.com/lightningnetwork/lnd/keychain"
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"github.com/lightningnetwork/lnd/shachain"
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)
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// nextRevocationProducer creates a new revocation producer, deriving the
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// revocation root by applying ECDH to a new key from our revocation root family
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// and the multisig key we use for the channel.
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func (l *LightningWallet) nextRevocationProducer(res *ChannelReservation,
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keyRing keychain.KeyRing) (shachain.Producer, error) {
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// Derive the next key in the revocation root family.
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nextRevocationKeyDesc, err := keyRing.DeriveNextKey(
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keychain.KeyFamilyRevocationRoot,
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)
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if err != nil {
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return nil, err
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}
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// If the DeriveNextKey call returns the first key with Index 0, we need
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// to re-derive the key as the keychain/btcwallet.go DerivePrivKey call
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// special-cases Index 0.
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if nextRevocationKeyDesc.Index == 0 {
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nextRevocationKeyDesc, err = keyRing.DeriveNextKey(
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keychain.KeyFamilyRevocationRoot,
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)
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if err != nil {
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return nil, err
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}
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}
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res.nextRevocationKeyLoc = nextRevocationKeyDesc.KeyLocator
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// Perform an ECDH operation between the private key described in
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// nextRevocationKeyDesc and our public multisig key. The result will be
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// used to seed the revocation producer.
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revRoot, err := l.ECDH(
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nextRevocationKeyDesc, res.ourContribution.MultiSigKey.PubKey,
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)
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if err != nil {
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return nil, err
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}
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// Once we have the root, we can then generate our shachain producer
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// and from that generate the per-commitment point.
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return shachain.NewRevocationProducer(revRoot), nil
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}
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