70 lines
1.7 KiB
Go
70 lines
1.7 KiB
Go
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//go:build !libsecp256k1
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package nostr
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import (
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"crypto/sha256"
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"encoding/hex"
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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 signature is valid for the id
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// (which is a hash of the serialized event content).
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// returns an error if the signature itself is invalid.
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func (evt Event) CheckSignature() (bool, error) {
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// read and check pubkey
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pk, err := hex.DecodeString(evt.PubKey)
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if err != nil {
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return false, fmt.Errorf("event pubkey '%s' is invalid hex: %w", evt.PubKey, err)
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}
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pubkey, err := schnorr.ParsePubKey(pk)
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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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s, err := hex.DecodeString(evt.Sig)
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if err != nil {
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return false, fmt.Errorf("signature '%s' is invalid hex: %w", evt.Sig, err)
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}
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sig, err := schnorr.ParseSignature(s)
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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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func (evt *Event) Sign(secretKey string, signOpts ...schnorr.SignOption) error {
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s, err := hex.DecodeString(secretKey)
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if err != nil {
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return fmt.Errorf("Sign called with invalid secret key '%s': %w", secretKey, err)
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}
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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(s)
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pkBytes := pk.SerializeCompressed()
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evt.PubKey = hex.EncodeToString(pkBytes[1:])
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h := sha256.Sum256(evt.Serialize())
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sig, err := schnorr.Sign(sk, h[:], signOpts...)
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if err != nil {
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return err
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}
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evt.ID = hex.EncodeToString(h[:])
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evt.Sig = hex.EncodeToString(sig.Serialize())
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return nil
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}
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