how to setup integration with CashU in asp.net?

Question

i want to add CashU Payment to my website when i setup the service the website generate to me an html form ` https://sandbox.cashu.com/cgi-bin/pcashu.cgi' method='post'>

<input  type='hidden'   name='merchant_id' value='xxxxxxx'/>
<input  type='hidden'   name='token' value='xxxxxx'/>
<input  type='hidden'   name='display_text' value='test service name'/>
<input  type='hidden'   name='currency' value='SAR'/>
<input  type='hidden'   name='amount' value='1'/>
<input  type='hidden'   name='language' value='en'/>
<input  type='hidden'   name='session_id' value=''/>
<input  type='hidden'   name='txt1' value='test service text'/>
<input  type='hidden'   name='txt2' value=''/>
<input  type='hidden'   name='txt3' value=''/>
<input  type='hidden'   name='txt4' value=''/>
<input  type='hidden'   name='txt5' value=''/>
<input  type='submit' name='but' value='Buy Now'/> </form`

when i write this in html page it works fine but i added in aspx page cause i want to change amount in page load

Response.Write("<SCRIPT LANGUAGE='JavaScript'>function myFunction(){ document.getElementById('o').value='"+ 50 +"';}</SCRIPT>");

and change

<input  type='hidden'   name='amount' value='1'/>
    <input  type='submit' name='but' value='Buy Now'/>

to

<input id="o"  type='hidden'   name='amount' value='1'/> 
    <input  type='submit' name='but' value='Buy Now' onclick='myFunction()'/>

i faced this screen how come this Error Image

how can i solve this problem i need help please .

Answer 1

if you change the amount then you need to recalculate the token. the token should be calculated like this ' MD5(“merchantid:amount:aed:encryption key”) '

Merchant id and currency must be in lowercase