Upvote:3
MasterCard SecureCode is a brand name for "3-D Secure" (also marketed as Verified By Visa) and these days it doesn't even ask a password any more which is not surprising because it's one of the worst form of security ever created, here's a paper titled Verified by Visa and MasterCard SecureCode: Or, How Not to Design Authentication.
Anyways it's not a requirement for a merchant to use it. In fact, only the card number is a requirement, everything else (even CCV2, the three digits on the back) just decreases the rate for the merchant because there's less fraud. See the answers to this question on Security SE.