My local bank uses a 2 factor authentication where customers key in password AND a One Time PIN delivered via SMS to mobile phone OR from a security token device.
I am doing a web startup in the ecommerce space.
I already have implemented https for important pages like login. I have chosen a, shall we say, cost effective SSL CA that has the initials GD.
This may be in the future, but what is a cost effective solution for me to implement a 2 factor authentication like my local bank for my users?
Which vendor would provide a cost effective solution just like I approached GD for my SSL certs?