The registration of software neither collects or stores private information about users or their computers. Registration uses an algorithm to condense unique information about a computer in such a manner that this condensed value uniquely identifies that computer (with a slight margin of error). This condensation of information is not and as such can provide no information about the computer or its user.
When processing a registration for a licensed copy of a software, your User ID and Passwords are also part of a uniquely calculated and condensed value identifier. As such both values are not stored in their original format. Also, since both the User ID and Passwords are already on record with records pertaining to your purchase, you are not supplying any new or sensitive information during registration.