Permanent Portable Avatar Identity Ownership
Avatar Identity in platforms like SL and Opensim are tied to UUID keys, which are already cryptographic, just not blockchain based. They are tied to the central server of a given grid the avatar is registered through.
As a result, when a grid goes down, or shuts down, the user's avatar identity is at the mercy of the grid operator. Some grids provide an Individual Asset Repository file, or IAR for each avatar and their inventory that they can load into another grid they might join, if the grid allows IARs to be loaded.
The problem with this technology is that the system is incapable of preserving original creator credits or next owner permissions, because the creator might not exist on the new grid, and the uploading system has to override the next owner permissions in order to transfer ownership from the original avatar UUID on their original grid, to the new avatar UUID on the new grid.
The same issue exists with region based OAR files that back up entire simulator region builds.
The logical incapability of this process to preserve creator IP rights makes it inherently illegal under DMCA and WIPO. Creator credits and next owner permissions must remain persistent on all platforms. The most effective way to accomplish this is to also divorce avatar identity from grids entirely, so their avatar name, UUID key (or other keys), as well as money and inventory are all independent of any one grid.
So, starting from first principles, any metaverse user registration system has to be independent of any given platform, grid, world etc. This type of passport system is already common on Web2.0, with logins to many websites using one's google, facebook, and twitter credentials. These services are, however, centralized, and therefore at the mercy of the onerous policies of those megacorporations interfering with peoples access to what should be their own property, their data.
The only way to give each person true independence and control of their avatar identity is as a NAME NFT on the blockchain. The NAME is akin to a domain name, but refers to an avatar identity. It sits in the crypto wallet of the user. A user can own multiple NAME NFTs just like they can own many domain names. They can sell those NAMEs. A NAME is independent of one's other crypto assets, in that one crypto wallet can own many NAMEs and many assets but the assets do not go with the NAME if the NAME is transferred. Thus the name is an asset like any other in one's inventory.
This concept of a NAME NFT has already been implemented in http://decentraland.org which works effectively. Decentraland is a blockchain based virtual world with a grid of 90,000 parcels and many 'realms', which are essentially shards of the same grid, so the same parcel can exist on many shards, but your name and inventory remain the same. Each shard is run by a different operator.
