(NOTES) NOTES (2023)

Google Recaptcha (code for ancient ASP)

Google has a lot of various API (List of Google API),I use Google service and my site contains a lot of pages of Google API, for example:

In other case about 2002 year I have wrote own capture API, and I used it in a lot of my projects since 2002 year, for example

`

And I have a lot of my own technology to protect rogue login, for example look to this page:

`

In third axis there are a lot of various technology to protect rogue login, for example.

This small explanation can help anybody what small background future for protect rogue login is Google recaptcha. But in some case customer select exactly this options and nothing else.

Therefore in this page I want to publish my workable code to ancient ASP.

So, firstly we can going to google and registered domain to Google recapture API https://www.google.com/recaptcha/admin. We can select V2 or V3 version.



That's it for Google.

Server solution.

Next step we need to go on own site and adding capture to Html. There are two way, this is first.


   346:  <script src="https://www.google.com/recaptcha/api.js" async defer></script>
   404:  <!--#include file="../Google/RecaptchaDiv.inc"-->

Where RecaptchaDiv.inc is only one DIV (this is useful to place keys related to Recaptcha to one site folder.




Second way.


   346:  <script src="https://www.google.com/recaptcha/api.js?onload=onloadCallback&render=explicit"></script>
   347:     <script type="text/javascript">
   348:          var onloadCallback = function () {
   349:              grecaptcha.render('recaptcha', {
   350:                  'sitekey': 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
   351:              });
   352:          };
   353:      </script>

And than we need place on Postback part the verification code (code from 41-90 is user login - select query with username and password to batabase and set AU cookie and needed session variables).


   23:          If Request.ServerVariables("REQUEST_METHOD") = "POST" Then
   24:   
   25:              if Request.Form("g-recaptcha-response") ="" then
   26:                  Response.Cookies("sfCustomer").Expires = Now()
   27:                  Errormsg = "Invalid Google captcha" 
   28:              else
   29:   
   30:  %>
   31:      <!--#include file="../Google/RecaptchaCheck.inc"-->
   32:  <%    
   33:                  Dim GoogleVerify
   34:                  GoogleVerify = RecaptchaConfirm (Request.Form("g-recaptcha-response"))
   35:                  if GoogleVerify <> "" then
   36:   
   37:                      Response.Cookies("sfCustomer").Expires = Now()
   38:                      Errormsg = "Invalid Google captcha" 
   39:   
   40:                  else
  19:   
  20:   
  21:                      Const vDebug = 0
  22:                      Dim iAuthenticate, custEmail, custPasswd, ErrorMsg, RPage, Arr,StrInvalidChar
  23:   
  24:                      if Request.QueryString = "" Then
  25:                          RPage = Request.Form ("Rpage")
  26:                      Else
  27:                          Arr = Split (Request.QueryString,"=",2,1)
  28:                          RPage = Arr(1)
  29:                      End if    
  30:   
  31:                      If Request.ServerVariables("REQUEST_METHOD") = "POST" Then    
  32:                          custEmail = Request.Form ("custEmail")
  33:                          custPasswd = Request.Form ("custPasswd")    
  34:                          StrInvalidChar = "',;,#,(,), ,?,%,--"
  35:   
  36:                          If CheckInvalidChar(custEmail ,StrInvalidChar) Or CheckInvalidChar(custPasswd,StrInvalidChar) Then
  37:                                  Errormsg = "Invalid Email & Password"
  38:                                  Response.Cookies("sfCustomer").Expires = Now()        
  39:                                  iAuthenticate = -110
  40:                          Else
  ..:      
  90:          End if
  91:      End if
  92:  End if
  93:  %>
  94:  <html>


And this is my code of RecaptchaCheck.inc, on the end of function you can see correct and wrong answer from Google.


   1:  <%
   2:    ' returns "" if correct, otherwise it returns the error response
   3:  Function RecaptchaConfirm(Token)
   4:   
   5:    if Token="" then 
   6:      RecaptchaConfirm = "No token"
   7:    else
   8:   
   9:        Dim  recaptcha_private_key, server_response, newCaptcha
  10:        recaptcha_private_key      = "YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY" '<------------------------------------------- your private key
  11:   
  12:        Dim VarString
  13:        VarString = _
  14:                "secret=" & recaptcha_private_key & _
  15:                "&remoteip=" & Request.ServerVariables("REMOTE_ADDR") & _
  16:                "&response=" & Token
  17:   
  18:        Dim objXmlHttp
  19:        Set objXmlHttp = Server.CreateObject("Msxml2.ServerXMLHTTP")
  20:        objXmlHttp.open "POST", "https://www.google.com/recaptcha/api/siteverify", False
  21:        objXmlHttp.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
  22:        objXmlHttp.send VarString
  23:   
  24:        Dim ResponseString
  25:        ResponseString = objXmlHttp.responseText
  26:        Set objXmlHttp = Nothing
  27:   
  28:        if InStr(1, ResponseString, "true") then
  29:          'They answered correctly
  30:           RecaptchaConfirm = ""
  31:        else
  32:          'They answered incorrectly
  33:           RecaptchaConfirm = ResponseString
  34:        end if
  35:    end if
  36:   
  37:  End Function
  38:   
  39:  %>
  40:   
  41:  <!--'    (0): "{"
  42:  '    (1): "  \"success\": false,"
  43:  '    (2): "  \"error-codes\": ["
  44:  '    (3): "    \"missing-input-secret\""
  45:  '    (4): "  ]"
  46:  '    (5): "}"
  47:  '
  48:  '    (0): "{"
  49:  '    (1): "  \"success\": true,"
  50:  '    (2): "  \"challenge_ts\": \"2023-05-03T22:52:47Z\","
  51:  '    (3): "  \"hostname\": \"localhost\""
  52:  '    (4): "}"-->


Client only checking.

In this case we will blocking postback to server. I'm sorry, I have no more time, please see solution on screenshot below.









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Link to this page: http://www.vb-net.com/GoogleRecaptcha/Index.htm
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