White paper
Decentraland is a virtual reality platform powered by the Ethereum blockchain. Users
can create, experience, and monetize content and applications. Land in Decentraland
is permanently owned by the community, giving them full control over their creations.
Users claim ownership of virtual land on a blockchain-based ledger of parcels.
Landowners control what content is published to their portion of land, which is
identified by a set of cartesian coordinates (x,y). Contents can range from static 3D
scenes to interactive systems such as games.
Land is a non-fungible, transferrable, scarce digital asset stored in an Ethereum smart
contract. It can be acquired by spending an ERC20 token called MANA. MANA can also
be used to make in-world purchases of digital goods and services.
People are spending increasingly more time in virtual worlds, for both leisure and
work
1
. This occurs predominantly in 2D interfaces such as the web and mobile phones.
But a traversable 3D world adds an immersive component as well as adjacency to
other content, enabling physical clusters of communities.
Unlike other virtual worlds and social networks, Decentraland is not controlled by a
centralized organization. There is no single agent with the power to modify the rules of
the soware, contents of land, economics of the currency, or prevent others from
accessing the world.
This document lays out the philosophical underpinnings, technical foundations, and
economic mechanisms of Decentraland.
Abstract
Esteban Ordano
esteban@decentraland.org
Ariel Meilich
ari@decentraland.org
Yemel Jardi
yemel@decentraland.org
Manuel Araoz
manuel@decentraland.org
A blockchain-based virtual world
Decentraland
Decentraland 1/14
1 The State of Mobile, Flurry Analytics Blog. https://flurrymobile.tumblr.com/post/155761509355
We would like to thank the following reviewers, whose contributions and feedback
made this document possible:
Jake Brukhman (Founder, CoinFund)
Luis Cuende (Project Lead, Aragon)
Simon de la Rouviere (ConsenSys)
Diego Doval (Founder of n3xt, previously CTO, Ning)
Michael Bosworth (Google)
Jesse Walden (Mediachain/Spotify)
Chris Burniske (ex ARK Invest)
Guillermo Rauch (CEO, Zeit)
Joe Urgo (Co-founder, District0x)
David Wachsman (Wachsman PR)
Jon Choi (Dropbox)
Allen Hsu
Decentraland 2/14
1 Introduction
1.1 Rationale
1.2 History
1.3 A Traversable World
1.4 Foundations for an In-world Economy
1.5 Use Cases
2 Architecture
2.1 Consensus Layer
2.2 Content Distribution Layer
2.3 Real-Time Layer
2.4 Payment Channels
2.5 Identity System
3 Economy
3.1 LAND and the MANA Token
3.2 Fostering the Network
4 Challenge
5 Summary
4
4
5
6
6
7
8
9
9
10
11
11
12
12
13
13
14
Table of Contents
Decentraland 3/14
Decentraland provides an infrastructure to support a shared virtual world, also known
as a metaverse
2
. It consists of a decentralized ledger for land ownership, a protocol for
describing the content of each land parcel, and a peer-to-peer network for user
interactions.
01 Introduction
The development of large proprietary platforms, such as Facebook, has allowed
hundreds of millions of users to gather, interact, share content, and play games. Their
network effects helped cultivate vast online communities and gaming companies.
These platforms, controlled by centralized organizations, manage the network’s rules
and content flow, while extracting significant revenue from the communities and
content creators who drive traffic to the platforms. Decentraland aims to establish a
network that allows its content creators to own and capture the full value of their
contributions.
The current team began working on Decentraland in 2015. At the time, the adoption of
cryptoassets was still in its infancy, as much of the blockchain-based infrastructure
necessary for a consumer-oriented platform was lacking. Since then, the rate of
consumer adoption and infrastructure creation has exploded. For instance, by July
2017, Coinbase alone reached 8.4 million user accounts, with half of these added over
the past 12 months
4
. This growth has given rise to a pool of users large enough to fuel
the decentralized commerce that will take place in a virtual world like Decentraland.
While blockchain infrastructure, spearheaded by Ethereum, is now more widely
available, the lack of an efficient method to quickly process micropayments constrains
the throughput of network transactions.
The maturation of cryptocurrencies as a global, instant, and low cost payment method
is still evolving. Payment transactions will need to occur off-chain to achieve short- to
medium-term scalability in blockchain payment networks. Solutions such as Bitcoin's
Lightning Network
5
or Ethereum's state channels
6
are on the verge of enabling a fast,
global payment system with low fees.
1.1 Rationale
01. Introduction 4/14
2 “The Metaverse”. Wikipedia. https://en.wikipedia.org/wiki/Metaverse
3 http://www.kccllc.net/thq/document/1213398130702000000000003
4 https://www.coinbase.com/about
5 “Lightning Apps and the Emerging Developer Ecosystem on LND”. Lightning Network’s Blog.
http://lightning.community/soware/lnd/lightning/2017/07/05/emerging-lightning-developer-ecosystem/
6 “Sprites: Payment Channels that Go Faster than Lightning”. A. Miller, I. Bentov, R. Kumaresan, P. McCorry, 2017.
https://arxiv.org/pdf/1702.05812.pdf
Figure 1: Stone Age. A
visual representation of
the blockchain state.
Users could mine,
transfer, and change the
color of pixels they own.
More centralized solutions can work today
7
, although at the expense of operability
with other systems, privacy, and standardization. Decentraland is built on the premise
that low cost, direct payments between content creators and users will radically
change internet commerce.
Decentraland began as a proof of concept for allocating ownership of digital real estate
to users on a blockchain. This digital real estate was initially implemented as a pixel on
an infinite 2D grid, where each pixel contained metadata identifying the owner and
describing the pixel's color. The experiment was entitled Decentraland’s Stone Age.
In late 2016, the team started developing the Bronze Age, a 3D virtual world divided
into land parcels. The owner of each parcel was able to associate it with a hash
reference to a file, using a modified Bitcoin blockchain. From this reference, users
exploring the virtual world could use a Distributed Hash Table (DHT) and BitTorrent to
download the file containing the parcel’s content, which defines the models and
textures to be displayed at that location.
We hosted the first world viewer at decentraland.org/world. Any enthusiast can run a
node, download and verify the blockchain, and explore the world by following more
advanced instructions
8
.
1.2 History
01. Introduction 5/14
Figure 2: Bronze Age.
Structures created by
the community around
the Genesis parcel,
located at coordinates
(0,0)
7 “Near-zero fee transactions with hub-and-spoke micropayments”. Peter Todd, bitcoin-development mailing list,
December 2014. https://www.mail-archive.com/bitcoin-development@lists.sourceforge.net/msg06576.html
8 https://github.com/decentraland/bronzeage-node#run-a-node
1.3 A Traversable World
The adjacency of land makes Decentraland parcels unique from web domains. New
land parcels must be contiguous to existing ones. This adjacency allows for spatial
discovery of new content and the creation of districts devoted to a special topic or
theme. While each web domain can have an unlimited number of hyperlinks to other
content, parcels in Decentraland have a fixed amount of adjacencies. Additionally, the
content of adjacent parcels can be seen from a distance. For content creators, the
establishment of districts provides access to targeted traffic; for end users, it enables
discovery of themed experiences. Users can travel through neighborhoods and
interact with applications that they stumble upon.
This discovery by adjacency is at odds with having infinite land: in that scenario, users
would have a hard time finding relevant content by traveling through it. With scarce
land, developers can acquire users by purchasing land in high-traffic areas. This will
allow secondary markets to develop around land ownership and rentals, as is already
happening on district0x.io.
9
9 https://blog.district0x.io/decentraland-districts-40b9ada0431b
The next version of Decentraland, the Iron Age, will create a social experience with an
economy driven by the existing layers of land ownership and content distribution. In
the Iron Age, developers will be able to create applications on top of Decentraland,
distribute them to other users, and monetize them.
The Iron Age will implement peer-to-peer communications, a scripting system to
enable interactive content, and a system of fast cryptocurrency payments for in-world
transactions. A communication layer is essential for social experiences, providing
positioning, postures, voice chat, and more; Decentraland achieves this with a P2P
network. The scripting system is the tool that landowners will use to describe the
behavior and interactions of 3D objects, sound, and applications running on land
parcels. Finally, a payment system with low fees is key to developing an economy in
the quick environment of a virtual world.
01. Introduction 6/14
Decentraland’s value proposition to application developers is that they can fully
capitalize on the economic interactions between their applications and users. To allow
those economic interactions, the platform must allow three things to be traded:
currency, goods, and services.
Decentraland will integrate a core system that allows global, instant, and cost-effective
payments between any two users on the internet. Cryptocurrencies allow for trustless
payment channels to be established between parties, with low-trust hub-and-spoke
systems already possible.
1.4 Foundations for an In-world Economy
10 “Rare Pepe”. Fred Wilson. https://avc.com/2017/05/rare-pepe/
01. Introduction 7/14
For services to be provided on Decentraland, we are developing a scripting system that
enables developers to program the interactions between users and applications. This
scripting system runs exclusively on the client side but allows for different data flow
models: from mere local effects and traditional client-server architectures, to P2P
interactions based on state channels. Developers programming in it will benefit from
the availability of fast, cheap micropayments, provably fair games, decentralized
storage, and other features enabled by the advent of cryptographic techniques using
blockchain-based smart contracts.
To foster the exchange of virtual goods, economic incentives must be in place to
ensure the continued creation and distribution of avatars, items, and scripts. Because
static content can be arbitrarily copied, the user experience should empower social
agreements that recognize original creations. By implementing an identity system to
establish authorship, users will be able to track and verify an author’s consent through
cryptographic signatures. These experiments are already happening, as in the case of
Rare Pepes
10
.
Applications
The Decentraland scripting language will allow the development of applications,
games, gambling, and dynamic 3D scenes. This scripting language will be designed to
handle a wide range of capabilities, including creating objects, loading textures,
handling physics, encoding user interactions, sounds, payments, and external calls,
among others.
Content Curation
Users in Decentraland will gather around neighborhoods of shared interest. Being
located near high-traffic hubs will drive users to the landowners’ content.
Advertising
Brands may advertise using billboards near, or in, high-traffic land parcels to promote
their products, services, and events. Some neighborhoods may become virtual
versions of Times Square in New York City. Additionally, brands may position products
and create shared experiences to engage with their audience.
Digital Collectibles
We expect users to publish, distribute, and collect rare digital assets issued on the
blockchain by their creators. Just as it occurs today in other virtual worlds or through
online forums, these digital assets will be traded inside this world through the
scripting system and be backed by the aforementioned naming system.
1.5 Use Cases
02. Architecture 8/14
Social
Groups that currently gather in online forums, chat groups, or even other centralized
multiplayer games could port their communities into Decentraland. Offline
communities could also find in Decentraland a space to gather.
Other use cases
There are no technical specifications to what could be built in Decentraland.
Therefore, other use cases could emerge, such as training and professional
development, education, therapy, 3D design, and virtual tourism, among others.
The Decentraland protocol is comprised of three layers:
02 Architecture
1) Consensus layer:
Track land ownership and its content.
2) Land content layer:
Download assets using a decentralized distribution system.
3) Real-time layer:
Enable users’ world viewers to connect to each other.
Land ownership is established at the consensus layer, where land content is
referenced through a hash of the file’s content. From this reference the content can be
downloaded from BitTorrent or IPFS. The downloaded file contains a description of
objects, textures, sounds, and other elements needed to render the scene. It also
contains the URL of a rendezvous server to coordinate connections between P2P users
that are exploring the tile simultaneously. Figure 3 shows a diagram of the steps the
Decentraland clients execute to provide the experience of a shared virtual world in a
decentralized way.
Figure 3: The
Decentraland protocol
for simultaneous users
in a decentralized
virtual world.
11 https://ipfs.io
12 https://filecoin.io/
02. Architecture 9/14
Decentraland will use an Ethereum smart contract to maintain a ledger of ownership
for land parcels in the virtual world. We call these non-fungible digital assets LAND:
each LAND has unique (x, y) coordinates, an owner, and a reference to the content
description file, which encodes what the landowner wants to serve there.
Decentraland clients will connect to the Ethereum network to fetch updates to the
state of the LAND smart contract.
LAND is bought by burning MANA, a fungible ERC20 token of fixed supply. This token
serves as a proxy for the cost of claiming a new parcel. The LAND contract uses a burn
function to destroy MANA and create a new entry in the LAND registry. New parcels
need to be adjacent to a non-empty parcel.
2.1 Consensus Layer
Decentraland uses a decentralized storage system to distribute the content needed to
render the world. For each parcel that needs to be rendered, a reference to a file with
the description of the parcel’s content is retrieved from the smart contract. The current
solution uses the battle-tested BitTorrent and Kademlia DHT networks by storing a
magnet link for each parcel. However, the Inter-Planetary File System (IPFS)
11
provides
a compelling alternative as its technology matures.
This decentralized distribution system allows Decentraland to work without the need
of any centralized server infrastructure. This allows the world to exist as long as it has
users distributing content, shiing the cost of running the system to the same actors
that benefit from it. It also provides Decentraland with strong censorship-resistance,
eliminating the power of a central authority to change the rules or prevent users from
participating.
However, hosting these files and the bandwidth required to serve this content has
significant costs. Currently, users of the Decentraland P2P network are seeding the
content without compensation and out of goodwill. However, in the future, this
infrastructure cost can be covered by the use of protocols like Filecoin
12
. Until this
technology becomes available, automated micropayments can be used to pay for
quality of service. The proceeds of Decentraland’s continuous sale of MANA can cover
these costs over the long run (see Section 3.2).
2.2 Content Distribution Layer
Additionally, two other systems are key for Decentraland’s economy to develop:
Payment Channel Infrastructure for fast payments with low fees.
Identity System that allows users to establish ownership over original creations.
02. Architecture 10/14
13 https://tools.ietf.org/html/rfc5389
14 https://webrtc.org/
The description of a parcel will contain a list of different files required to render it, a list
of services hosted by the landowner, and an entry point to orchestrate the placement
of objects and their behavior. This document must declare:
Content files
References to, or blobs with, 3D meshes, as well as textures, audio files, and other
relevant content required to render the parcel. These are specified so that the client
knows what contents the renderization will need, without any instructions on how to
place them.
Scripting entry point
The scripting system controls how the content is placed in the parcel, as well as its
behavior. This enables applications and animations to take place within the parcel. It
also coordinates behaviors such as the positioning and movement of objects, the
timing and frequency of sounds played, the possible interactions with users, among
other features.
P2P interactions
This allows the client to connect to a server that bootstraps user-to-user connections,
coordinates positions and postures, and enables voice chat and messaging.
Clients will communicate with each other by establishing peer-to-peer connections
with the help of servers hosted by landowners or third parties. Without a centralized
server, peer-to-peer connections are needed to provide social interactions between
users, as well as applications that the landowner wants to run inside the parcel. To
coordinate the bootstrap of peer-to-peer connections, landowners will have to provide
rendezvous servers or understand that users will not be able to see each other in their
parcel.
The maintenance of these servers can be incentivized the same way as content
servers. When lightweight protocols like STUN
13
can cover the functionality required
from the server, the costs would be fairly low. But for more advanced features, such as
a voice chat between multiple concurrent users or network traversal services,
micropayments can be used to cover the operating costs.
The social experience of users in Decentraland will include avatars, the positioning of
other users, voice chat, messaging, and interaction with the virtual environment. The
different protocols used to coordinate these features can work on top of existing P2P
solutions like Federated VoIP or WebRTC.
14
2.3 Real-Time Layer
02. Architecture 11/14
General purpose, public, and distributed HTLC networks like Lightning may be at least
one year away from materializing, but low-trust hub-and-spoke payment channel
networks allow for fast and low-cost transactions that can be implemented today.
Payment channels are key for Decentraland for two reasons:
In-world purchases
Incentivizing quality of service of content and P2P servers
Today, platforms mitigate the risk inherent in credit card payments: users trust the
platform, rather than the application, with their payment details. With payment
channels, they could make direct purchases to the developer with no risk of identity
the.
Some parts of Decentraland’s infrastructure can be paid for with micropayments.
These costs include hosting content, serving it, and running P2P protocols like spatial
audio processing for multiple users. The marginal cost of running applications on
Decentraland for developers, given a market of incentivized servers to provide the
infrastructure, approaches its real cost as this becomes essentially commoditized.
However, in order to have no barrier to entry for incoming developers, Decentraland
will subsidize these services with the proceeds of selling MANA tokens.
2.4 Payment Channels
Decentraland’s ownership of land is one kind of identity system, where credentials are
the coordinates of one’s land. Economic incentives are also necessary to ensure that
the creators of avatars, items, and scripts continue building and distributing them.
Since content can be arbitrarily copied, we must rely in social agreements to enforce
retribution to the creator.
Social agreements can make digital scarcity possible. In centralized systems, this
scarcity is defended by the company that creates the platform. For Bitcoin and other
proof-of-work blockchains, scarcity is enabled by a computational puzzle and the fact
that mining blocks requires an onerous economic sacrifice.
Decentraland can use decentralized identity systems to create a layer of ownership
over in-world items. This system must allow users to easily verify the consent of an
author by linking public keys and signatures with human-readable names.
2.5 Identity System
03. Economy 12/14
15 https://www.uport.me/
16 The Ethereum Name System is one of the most successful projects in this area: https://ens.domains/
17 http://www.mediachain.io/
18 “Curation Clubs: Tokenizing & Incentivizing Public Funding With Curation Markets”. Simon de la Rouviere. 2017.
https://medium.com/@simondlr/276613e641f0
19 http://avc.com/2017/05/rare-pepe/
3.1 LAND and the MANA Token
In Section 1.1, we make a case for how the increasing adoption of cryptocurrencies
creates the necessary conditions for the emergence of a distributed platform for a
virtual world. Below, we introduce the utility of LAND and the MANA token, how their
strategic allocation can help bootstrap the utility of the network, and outline how the
issuance of MANA will be conducted.
With the launch of the Iron Age, we are introducing two digital assets: LAND, the
non-fungible parcels in which the virtual world is divided; and MANA, an ERC-20 token
that is burned to claim LAND, as well as to make in-world purchases of goods and
services.
The utility of LAND is based on its adjacency to other attention hubs, its ability to host
applications, and also as an identity mechanism. Developers and other content
creators will demand LAND so that they can build on top of it and reach their target
audience. Although every unclaimed LAND can be purchased at the same exchange
rate (1000 MANA = 1 LAND), LAND parcels are distinguishable from each other,
potentially trading at different prices on a secondary market due to differences in
adjacencies and traffic.
On the other hand, MANA serves as a proxy to asses the price of a new parcel of LAND.
Also, MANA used to buy goods and services in the virtual world creates utility value for
the token.
03 Economy
Projects like uPort
15
or the Ethereum Name Service
16
can be used to do this. Social
reputation is also needed to facilitate contributions to the author.
The ability to incentivize content creation on decentralized economies is evolving
quickly, with multiple projects working in the space directly or indirectly. Potential
solutions include Mediachain
17
, Curation Markets
18
, Rare Pepes
19
, and more.
04. Challenges 13/14
3.2 Fostering the Network
Land ownership is acquired through an ERC-20 token called MANA. This token will
serve to bring value into the network, and to acquire a new parcel of land. MANA can
also be used to purchase in-world goods and services.
In order to jumpstart the network, developers and content creators will be rewarded
to set up shop in Decentraland. The Foundation will hold contests to create art,
games, applications, and experiences, with prizes contingent on meeting a set of
milestones. At the same time, new users will be assigned allowances, allowing them
to participate in the economy immediately. These financial incentives will help
bootstrap the utility value of the network until it independently attracts users and
developers.
04 Challenges
Decentralized Content Distribution
Content distribution through a P2P network has two main issues. The first involves
download speed: retrieving a file from a DHT or distributed peer-to-peer storage
system has traditionally been too slow. Specially, in a graphical application like
Decentraland, users will be adverse to using a system that does not load the
experience quickly. The second issue involves availability: ensuring that content is
sufficiently distributed around the network without loss. IPFS and the upcoming
FileCoin protocol are addressing these issues and we’re looking forward to when they
become production ready.
Scripting
Scripting will be the most important element used to create valuable experiences for
users in Decentraland. Its APIs will need to be secure enough for clients to hold private
keys and authorize micropayments frequently. Ease-of-use is also critical to penetrate
a broad audience of developers.
Content Curation
The issue of filtering content for mature audiences (like pornography, violence, or
gambling) is difficult to solve within a decentralized network. We expect a market to
emerge here: with a reputation-based approach, users could select one or more
providers of whitelists/blacklists that track the type of content being served on each
parcel.
05. Summary 14/14
05 Summary
Decentraland is a distributed platform for a shared virtual world that enables
developers to build and monetize applications on top of it. The scarcity of land, on top
of which applications can be built, creates hubs that capture user attention, which
drives revenue to content creators. MANA tokens will be used to purchase land, goods,
and services in-world. MANA tokens will also be used to incentivize content creation
and user adoption, therefore bootstrapping the first decentralized virtual world.