when open LIFF bodyEncryptString := string(req.Data) decodedMsgWithHmac, err := base64.StdEncoding.DecodeString(bodyEncryptString) //Handle error hMacCli := decodedMsgWithHmac[:BlockSizeHmac] decodedMsg := decodedMsgWithHmac[BlockSizeHmac:] statusHMac := ValidMAC(decodedMsg, hMacCli, []byte(salt)) //Validate HMAC iv := decodedMsg[:NONCESIZE] msg := decodedMsg[NONCESIZE:] //decrypt Body bodyDecryptString, err := DecryptAES([]byte(key), msg, iv)