60 lines
1.5 KiB
Go
60 lines
1.5 KiB
Go
//go:build !libsecp256k1
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package nostr
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import (
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"crypto/sha256"
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"fmt"
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"github.com/btcsuite/btcd/btcec/v2"
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"github.com/btcsuite/btcd/btcec/v2/schnorr"
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)
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// CheckSignature checks if the event signature is valid for the given event.
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// It won't look at the ID field, instead it will recompute the id from the entire event body.
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// If the signature is invalid bool will be false and err will be set.
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func (evt Event) CheckSignature() (bool, error) {
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// read and check pubkey
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pubkey, err := schnorr.ParsePubKey(evt.PubKey[:])
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if err != nil {
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return false, fmt.Errorf("event has invalid pubkey '%s': %w", evt.PubKey, err)
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}
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// read signature
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sig, err := schnorr.ParseSignature(evt.Sig[:])
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if err != nil {
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return false, fmt.Errorf("failed to parse signature: %w", err)
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}
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// check signature
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hash := sha256.Sum256(evt.Serialize())
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return sig.Verify(hash[:], pubkey), nil
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}
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// Sign signs an event with a given privateKey.
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//
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// It sets the event's ID, PubKey, and Sig fields.
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//
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// Returns an error if the private key is invalid or if signing fails.
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func (evt *Event) Sign(secretKey [32]byte) error {
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if evt.Tags == nil {
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evt.Tags = make(Tags, 0)
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}
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sk, pk := btcec.PrivKeyFromBytes(secretKey[:])
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pkBytes := pk.SerializeCompressed()[1:]
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evt.PubKey = [32]byte(pkBytes)
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h := sha256.Sum256(evt.Serialize())
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sig, err := schnorr.Sign(sk, h[:], schnorr.FastSign())
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if err != nil {
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return err
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}
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evt.ID = h
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sigb := sig.Serialize()
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evt.Sig = [64]byte(sigb)
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return nil
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}
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