[relay] Improve relay messages (#2574)

Co-authored-by: Zoltán Papp <zoltan.pmail@gmail.com>

relay/auth/hmac/v2/algo.go

@@ -0,0 +1,40 @@
+package v2
+
+import (
+	"crypto/sha256"
+	"hash"
+)
+
+const (
+	AuthAlgoUnknown AuthAlgo = iota
+	AuthAlgoHMACSHA256
+)
+
+type AuthAlgo uint8
+
+func (a AuthAlgo) String() string {
+	switch a {
+	case AuthAlgoHMACSHA256:
+		return "HMAC-SHA256"
+	default:
+		return "Unknown"
+	}
+}
+
+func (a AuthAlgo) New() func() hash.Hash {
+	switch a {
+	case AuthAlgoHMACSHA256:
+		return sha256.New
+	default:
+		return nil
+	}
+}
+
+func (a AuthAlgo) Size() int {
+	switch a {
+	case AuthAlgoHMACSHA256:
+		return sha256.Size
+	default:
+		return 0
+	}
+}