The user tables are ubbt_USERS, ubbt_USER_DATA, ubbt_USER_GROUPS, ubbt_USER_NOTES, ubbt_USER_PROFILE. Of these the tables that must be populated for each user would be ubbt_USERS, ubbt_USER_DATA, ubbt_USER_GROUPS, ubbt_USER_PROFILE.

Well, it's just an MD5 hash, no salt, so no "encryption" necessary.

I'd recommend doing a dummy install and creating a couple of users so you can see the data each table is going to require.

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