How to split a string received via a GSM module (message)
Simplest solution is to use sscanf().

  int password;
  char operation;
  int time;
  char* buf = "{14:C:123}";
  int n = sscanf(buf, "{%d:%c:%d}", &amp;password, &amp;operation, &amp;time);
  Serial.print(F("n="));
  Serial.println(n);
  Serial.print(F("password="));
  Serial.println(password);
  Serial.print(F("operation="));
  Serial.println(operation);
  Serial.print(F("time="));
  Serial.println(time);