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https://github.com/btcsuite/btcd.git
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abeaf4e334
In this commit, we add a new signatureVerifier interface that will allow us to consolidate a lot of code as we'll now have 4 distinct sig+sighash types to verify: 1. pre-segwit 2. segwit v0 3. segwit v1 (taproot key spend) 4. tapscript spends We'll need to be able to handle 3 of the cases for the modified OP_CHECKSIG operator. This new abstraction allows us to keep the implementation of the function somewhat succinct. In this commit we implement a verifier for #3 which is needed to verify the top-level taproot keyspend. We expose the verifier using a new VerifyTaprootKeySpend function.
50 lines
1.4 KiB
Go
50 lines
1.4 KiB
Go
package txscript
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import (
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"fmt"
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"github.com/btcsuite/btcd/wire"
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)
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// VerifyTaprootKeySpend attempts to verify a top-level taproot key spend,
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// returning a non-nil error if the passed signature is invalid. If a sigCache
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// is passed in, then the sig cache will be consulted to skip full verification
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// of a signature that has already been seen. Witness program here should be
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// the 32-byte x-only schnorr output public key.
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//
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// NOTE: The TxSigHashes MUST be passed in and fully populated.
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func VerifyTaprootKeySpend(witnessProgram []byte, rawSig []byte, tx *wire.MsgTx,
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inputIndex int, prevOuts PrevOutputFetcher, hashCache *TxSigHashes,
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sigCache *SigCache) error {
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// First, we'll need to extract the public key from the witness
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// program.
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rawKey := witnessProgram
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// Extract the annex if it exists, so we can compute the proper proper
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// sighash below.
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var annex []byte
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witness := tx.TxIn[inputIndex].Witness
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if isAnnexedWitness(witness) {
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annex, _ = extractAnnex(witness)
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}
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// Now that we have the public key, we can create a new top-level
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// keyspend verifier that'll handle all the sighash and schnorr
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// specifics for us.
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keySpendVerifier, err := newTaprootSigVerifier(
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rawKey, rawSig, tx, inputIndex, prevOuts, sigCache,
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hashCache, annex,
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)
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if err != nil {
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return err
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}
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valid := keySpendVerifier.Verify()
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if valid {
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return nil
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}
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// TODO(roasbeef): add proper error
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return fmt.Errorf("invalid sig")
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}
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