This OTP will be a single use password that will expire immediately on completion of the transaction. If the transaction is not processed then the OTP will have an expiry time of maximum 2 hours. It will entirely depend upon the bank's policy, Citi Bank claims that their OTP if not utilized will expire in 5 minutes.
With the security design in place, customers would need 5 sets of information to carry out a credit card transaction over phone:
1] The 16-digit card number
2] Card expiry date
3] CVV (Card Verification Value, which is printed on the back of the card) number,
4] Mobile number
5] The OTP.
The most important point to remember here is that your mobile number must be registered with the bank.
How the OTP works for various banks:
OTP should reach you by SMS on the registered mobile number while carrying out the transaction.
Send SMS: 'PWD (last 4 digits of credit card)' to 9717465555 from your registered mobile.
Send an SMS 'IOTP (last 4 digits of credit card)' to 5676766 from your registered mobile.
Send an SMS 'OTP (last 4 digits of credit card)' to 9880752484 from your registered mobile.
Send an SMS 'OTP (last 4 digits of credit card)' to 5676791 from your registered mobile.