lnwallet: add TweakPubKeyWithTweak helper function

This commit adds a new helper function which is identical to
TweakPubkey, but lets the caller specify their own hash tweak.
This commit is contained in:
Olaoluwa Osuntokun 2017-07-30 17:42:35 -07:00
parent 899fa1ea3e
commit 07b0604458
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1 changed files with 14 additions and 0 deletions

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@ -1005,6 +1005,20 @@ func TweakPubKey(basePoint, commitPoint *btcec.PublicKey) *btcec.PublicKey {
}
}
// TweakPubKeyWithTweak is the exact same as the TweakPubKey function, however
// it accepts the raw tweak bytes directly rather than the commitment point.
func TweakPubKeyWithTweak(pubKey *btcec.PublicKey, tweakBytes []byte) *btcec.PublicKey {
tweakX, tweakY := btcec.S256().ScalarBaseMult(tweakBytes)
x, y := btcec.S256().Add(pubKey.X, pubKey.Y, tweakX, tweakY)
return &btcec.PublicKey{
X: x,
Y: y,
Curve: btcec.S256(),
}
}
// TweakPrivKek tweaks the private key of a public base point given a per
// commitment point. The per commitment secret is the revealed revocation
// secret for the commitment state in question. This private key will only need