diff --git a/Sources/Models/HCert.swift b/Sources/Models/HCert.swift
index 945adcc..8b6142f 100644
--- a/Sources/Models/HCert.swift
+++ b/Sources/Models/HCert.swift
@@ -145,11 +145,13 @@ public struct HCert {
   
   public init?(from payload: String, errors: ParseErrors? = nil) {
     
+    let payload = payload
     if Self.checkCH1PreffixExist(payload) {
       fullPayloadString = payload
       payloadString = Self.parsePrefix(payload)
     } else {
-      fullPayloadString = Self.supportedPrefixes.first ?? "" + payload
+      fullPayloadString = Self.supportedPrefixes.first ?? ""
+      fullPayloadString = fullPayloadString + payload
       payloadString = payload
     }