Release v2.2.0

vendor/github.com/fiatjaf/go-lnurl/auth.go

@@ -0,0 +1,55 @@
+package lnurl
+
+import (
+	"encoding/hex"
+	"errors"
+	"net/url"
+
+	"github.com/btcsuite/btcd/btcec"
+)
+
+type LNURLAuthParams struct {
+	Tag      string
+	K1       string
+	Callback string
+	Host     string
+}
+
+func (_ LNURLAuthParams) LNURLKind() string { return "lnurl-auth" }
+
+// VerifySignature takes the hex-encoded parameters passed to an lnurl-login endpoint and verifies
+// the signature against the key and challenge.
+func VerifySignature(k1, sig, key string) (ok bool, err error) {
+	bk1, err1 := hex.DecodeString(k1)
+	bsig, err2 := hex.DecodeString(sig)
+	bkey, err3 := hex.DecodeString(key)
+	if err1 != nil || err2 != nil || err3 != nil {
+		return false, errors.New("Failed to decode hex.")
+	}
+
+	pubkey, err := btcec.ParsePubKey(bkey, btcec.S256())
+	if err != nil {
+		return false, errors.New("Failed to parse pubkey: " + err.Error())
+	}
+
+	signature, err := btcec.ParseDERSignature(bsig, btcec.S256())
+	if err != nil {
+		return false, errors.New("Failed to parse signature: " + err.Error())
+	}
+
+	return signature.Verify(bk1, pubkey), nil
+}
+
+func HandleAuth(rawurl string, parsed *url.URL, query url.Values) (LNURLParams, error) {
+	k1 := query.Get("k1")
+	if _, err := hex.DecodeString(k1); err != nil || len(k1) != 64 {
+		return nil, errors.New("k1 is not a valid 32-byte hex-encoded string.")
+	}
+
+	return LNURLAuthParams{
+		Tag:      "login",
+		K1:       k1,
+		Callback: rawurl,
+		Host:     parsed.Host,
+	}, nil
+}