3D Secure is a culmination of Verified by Visa or MasterCard Secure Code. 3D Secure is the latest fraud prevention initiative launched by the card schemes as a more secure method for authenticating the cardholder at the time of the transaction. This prevents misuse of your card and fraudulent transactions.
If your card is part of the scheme and you have already registered, then you will be redirected to the Verified by Visa/MasterCard Secure Code website to enter your password. If you haven't registered then you will be invited to do so and it only takes seconds. If your card is not part of the scheme yet, then you won't see the extra checks.