Whats the best measures to prevent greifing and stealing

You can make a sky base and have a secret way up that way a mod could easily be able to find out who griefed

I asked about the obsidian vault and its a no because its considered pvp

I am going to be building a modern house on the ground because I've never font one before, it will probably be the easiest to grief but not if I go 20-80 k blocks out

If I build a base I plan on keeping secret I build it underwater. If such a base is well placed and has no connections to the surface it is extremely hard to detect. If you build one keep these things in mind.
1. Build at least 4000 blocks out, that may not seem like much next to the fugues above but it's far enough. The further out it is, the less likely it will be found
2. Hide your nether portal. Place your portal behind a wall or underground in the nether to avoid detection.
3. Sever all connections with the surface ASAP.
4. Only give people who you trust the cords. A single person can kill the entire base.
5. There's not much you can do about live map other than make a big base. Live map shows a persons location, not depth, if you move around often it is much harder to determine what you're doing.
6. Have fun! EMC has wonderful staff who can help if you get greifed, if you're too busy worrying about greifed you won't get to have fun.
Hope this helps, if you want more guidance I do awnser PMs.