The order with reference code [xxx] could not be processed, the sign is not valid PayU

Question

I am trying to implement Pay U payment gateway in my web application.

I using a sample form to post payment values in the PayU form.

Please see my code below.

<form method="post" action="https://gateway.payulatam.com/ppp-web-gateway/">
<input name="merchantId" type="hidden" value="XXXXXX">
<input name="accountId" type="hidden" value="XXXXXX">
<input name="description" type="hidden" value="Test PAYU">
<input name="referenceCode" type="hidden" value="payment_test_00000001">
<input name="amount" type="hidden" value="3">
<input name="tax" type="hidden" value="0">
<input name="taxReturnBase" type="hidden" value="0">
<input name="currency" type="hidden" value="USD">
<input name="signature" type="hidden" value="be2f083cb3391c84fdf5fd6176801278">
<input name="test" type="hidden" value="1">
<input name="buyerEmail" type="hidden" value="[email protected]">
<input name="responseUrl" type="hidden" value="http://www.test.com/response">
<input name="confirmationUrl" type="hidden" value="http://www.test.com/confirmation">
<input name="Submit" type="submit" value="Enviar">

but I getting this error:

Answer 1

It's my mistake. Because the signature is not a MD5 string.

<input name="signature" type="hidden" value="be2f083cb3391c84fdf5fd6176801278">

it's need to write a new function for create MD5 string.

    public static string CalculateMD5Hash(string input)
    {
        // step 1, calculate MD5 hash from input
        MD5 md5 = System.Security.Cryptography.MD5.Create();
        byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
        byte[] hash = md5.ComputeHash(inputBytes);

        // step 2, convert byte array to hex string
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < hash.Length; i++)
        {
            sb.Append(hash[i].ToString("x2"));
        }
        return sb.ToString();
    }

then call this function like below.

        string Signature = CommonHelper.CalculateMD5Hash(ApiKey + "~" + MerchantId + "~" + ReferenceCode + "~" + Amount + "~" + Currency);

(Please keep the parameter order in above function.)

Now the signature is created.

pass this signature in the form.

Works fine.

:)

y