VIP Enterprise Gateway has a validation option of using Access PIN. This solution provides steps to enable and set it up.

1.    In order to use PIN option, go to VIP Manager > Account tab > VIP Policy configuration > click on Edit > set PIN = yes. Save changes.
2.    On the VIP Enterprise, create a RADIUS validation server Choose User ID + Access PIN + Security code as Validation Mode. Or, set validation to 'VIP Service' for an existing RADIUS validation server. 
3.    The user can set their PIN via Self Service Portal or My VIP. As an administrator, you may add each PIN for each user at VIP Manager > Users > Select a User > Edit details > Add PIN
4.    The following is a sample command using the vsradiusclient_test tool (under EG installation directory > Tools) to verify the functionality of the RADIUS client when the Validation server is configured in User ID - Access PIN - Security Code mode.
In this example, the password is a combination of the user’s Access PIN and the security code.
./vsradiusclient_test --server-host 10.10.0.10 --server-port 1812 --client-ip 10.10.0.12 --secret myradiussecret --user-name user1 --password user1apin940682

VIP Enterprise Gateway Installation & Configuration: User ID - Access PIN - Security Code