HDFC Bank from 1st of February 2011 is offering an extra layer of protection for online IVR Transactions by offering one-time password service.
With online transactions, HDFC and all Indian banks are already offering SourceSafe password but SourceSafe passwords were not needed for IVR transactions so as per RBI orders, similar password feature has also been enabled by HDFC Bank for IVR (on phone) transactions of credit cards
How do HDFC OTP (one-time password) works?
When making any IVR Transaction/Purchase from HDFC credit cards, the user has to send an SMS to 9717465555 with text as PWD <last_4_digits_of_credit_card>, for e.g. PWD 1234 and the password will come on the phone.
The password for IVR transaction will remain valid for 1 hour and will only be sent to the phone which is registered with that HDFC credit card.