add libsecp256k1 wrapper for sign/verify.

libsecp256k1/verify.go

@@ -0,0 +1,26 @@
+package libsecp256k1
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+
+	"github.com/nbd-wtf/go-nostr"
+)
+
+func (c *Context) CheckSignature(evt *nostr.Event) (bool, error) {
+	var pk [32]byte
+	_, err := hex.Decode(pk[:], []byte(evt.PubKey))
+	if err != nil {
+		return false, fmt.Errorf("event pubkey '%s' is invalid hex: %w", evt.PubKey, err)
+	}
+
+	var sig [64]byte
+	_, err = hex.Decode(sig[:], []byte(evt.Sig))
+	if err != nil {
+		return false, fmt.Errorf("event signature '%s' is invalid hex: %w", evt.Sig, err)
+	}
+
+	msg := sha256.Sum256(evt.Serialize())
+	return c.Verify(msg, sig, pk), nil
+}