The following example will demonstrate what is needed to perform the correct computation of the algorithm:
Note: 'pg_ts_hash' was computed like this:
pg_ts_hash=HMAC-MD5("APILOGINID|10|1.0|5.00|634094514514687490|100055", "SECURETRANSACTIONKEY")
Have you generated your API Login ID and Secure Transaction Key? If not, you’ll need to log into our gateway under “Gateway Settings”>Gateway Key and generate both items; https://sandbox.paymentsgateway.net/vt3/login.aspx.