You will have to follow two things in order to get query parameters encrypted for each profile, in such a way that it generates personalized preference center url when a user clicks. I see that you want to get email & country data for each of the profile to be encrypted.
1. First thing you will have to encrypt the email & country using the "encryption_aescbcEncrypt" function available by adding them as additional data on workflow query activity. Refer this page for list of functions: List of functions.
For example: encryption_aescbcEncrypt(@email, "\x4839dmjslekws482dks", "\xdfjskl30204dxms492")
2. Then create content block with the expression alias you see on the additional data.
For email encryption could be something: <%= context.targetData.expr1 %>
Similarly you will have one for country encryption which is <%= context.targetData.expr2 %>