[Paymill] Whether 3D Secure is supported?

Yes:

We are pleased that we can offer you the safe 3-D Secure credit card payment. This relieves you from most fraud problems that may arise and ensures you your amounts paid.

We’ll integrate it into PAYMILL for security reasons and will only accept payments from 01.11.2012 with 3-D Secure by default, if the card is enabled for it. For further questions about 3-D Secure please contact our Support team.

https://developers.paymill.com/guides/introduction/payment-processing#3-3-d-secure