Initial QSfera import

Server/vendor/github.com/lestrrat-go/dsig-secp256k1/secp256k1.go

@@ -0,0 +1,29 @@
+package dsigsecp256k1
+
+import (
+	"crypto"
+
+	"github.com/decred/dcrd/dcrec/secp256k1/v4"
+	"github.com/lestrrat-go/dsig"
+)
+
+const ECDSAWithSecp256k1AndSHA256 = "ECDSA_WITH_SECP256K1_AND_SHA256"
+
+// init adds secp256k1 support when the dsig_secp256k1 build tag is used.
+func init() {
+	// Register ES256K (secp256k1 + SHA256) support using the new API
+	err := dsig.RegisterAlgorithm(ECDSAWithSecp256k1AndSHA256, dsig.AlgorithmInfo{
+		Family: dsig.ECDSA,
+		Meta: dsig.ECDSAFamilyMeta{
+			Hash: crypto.SHA256,
+		},
+	})
+	if err != nil {
+		panic("failed to register secp256k1 algorithm: " + err.Error())
+	}
+}
+
+// secp256k1Curve returns the secp256k1 curve.
+func Curve() *secp256k1.KoblitzCurve {
+	return secp256k1.S256()
+}