I created a search result page. User who has no login/password can see the search result but it is read only while user with login/password can do more with the search result.

My page is started with: 

<CFIFIsDefined("url.uid") >   

    <CFSET userid ="#Decrypt(url.uid,application.mySecretKey,"AES","hex")#">

This page is doing just fine except when user left the page idle for sometime then comes back and refresh the page. That's the time when

an error shows up:

It seems that CF can't decrypt the url.uid after the page becomes idle for awhile.

The error:

My Application.cfc looks like this: 

<cfcomponent name="Application">

    <cfscript>
        this.name = "TWI";
        this.applicationTimeout = createTimeSpan(0,1,0,0);
        this.clientManagement = false;
        this.sessionManagement = true;
        this.sessionTimeout = createTimeSpan(0,1,0,0); 
    </cfscript>

    <cffunction name="onApplicationStart" returnType="boolean" output="false"> 
  <cfset application.dsn = "TWI">
  <cfset application.mySecretKey = generateSecretKey("AES")> 
        <cfreturn true /> 
    </cffunction>

   <cffunction name="onRequestStart" returnType="string" output="false">
     <cfset request.mySecretKey = application.mySecretKey />
     <cfset request.algorithm = "AES" />
     <cfset request.encoding = "hex" />
   </cffunction>

    <cffunction name="onApplicationEnd" returnType="void" output="false">
        <cfargument name="applicationScope" required="true" />
 
        <cfreturn />
    </cffunction>

    <cffunction name="OnSessionStart" access="public" returntype="void" output="false">
 
  <CFSET session.EntityId= "0">
  <CFSET session.Roles="">
 
        <cfreturn />
    </cffunction>
  
    <cffunction name="OnSessionEnd" access="public" returntype="void" output="false">
        <cfargument name="SessionScope" type="struct" required="true" />
        <cfargument name="ApplicationScope" type="struct" required="false" default="#StructNew()#" /> 
    
        <cfreturn />
    </cffunction>

</cfcomponent>

What should I do to avoid this error showing up again? Have I done something wrong if the codes in my application.cfc or there is something else I haven't done?

For other pages where only users with login/password can access, I started the code with: 

<CFIF session.EntityId IS 0>

    <cflocation url="index.cfm">

<CFELSE>

   <!--- Codes here --->  

</CFIF>

With these codes on top of the page, if user left the page idle for awhile then comes back and refresh, I did not get the error because  the site will go back to idex.cfm

I can't do this to the search page because users without login/password are allowed to search and see the search result.  Can anyone help with solution?