Introduction to Smart Contracts and their States
Last updated
Last updated
Before addressing the technical implementation of RGB states and the related data structure, it is important to remember that the ordered sequence of single-use seals is intended to provide the ability to properly implement the various Contract Operations in the client-side validated domain.
After a brief introduction to smart contracts and state concepts, we will devote our attention to the mechanism behind Contract Operations from the the Client-side perspective and the related bridging points which tether these operations to the Bitcoin Blockchain commitments discussed in the commitment layer section.
Since RGB allows for the implementation of smart contracts in Bitcoin, it is a good time to define what a smart contract actually is.
A smart contract is an agreement which is automatically and computationally enforced between the parties.
This means that the enforcement of the terms agreed upon between the parties does not require human intervention and that such enforcement is carried out by mathematical and computerized means.
Furthermore, a question arises. To achieve the highest degree of automation, decentralization, and privacy, is it possible to forfeit the use of a centralized registry that stores ownership and contract information? The affirmative answer lies back at the origins.
Not long times ago, contracts, such as securities, were bearer instruments. Indeed, the widespread use of asset registers that imply a custodial relationship with some institution on behalf of the client is a fairly recent development in economic history. The bearer nature of contracts is, in fact, a centuries-old tradition. This type of philosophy is the basis of the RGB architecture, in that the bearer rights of each claimant are contained in the form of data within the contract and can be modified and applied digitally, following the rules of the contract itself.
A wider range of smart contract programmability issues were considered in the design of RGB, in particular:
A contract can be associated with a digital asset or a token, but it's not limited to it. A broader range of applications and extensions of the smart contract concept can be implemented in RGB.
Unlike the approach of other public blockchains to smart contracts, in RGB there is a clear separation between the different parties related to a contract and their rights: e.g. the creator/issuer of the contract and the different kinds of users interacting in some ways with the contract. This includes, in particular, the differentiation between:
the ability to observe certain properties or operations performed by other parties on the contract;
the ability to execute a set of operations permitted by the contract.
No other counterparty can interact with the operations performed on the contract unless it is authorized by the rightful parties. Within RGB this feature means that there is always an owner that has the right to perform certain operations on the contract, which are defined by the contract itself.
These properties combined allow for two of the most important properties at the heart of the RGB value proposition, which are: scalability and censorship resistance at unprecedented levels.
In order to achieve these goals, an RGB contract is composed of two main components:
State
Business Logic (Behavior)
The Business Logic of the contract represents the rules that allow the entitled parties to change the state of the contract. We will find out later that the Business Logic is embedded in a particular structure of the contract called the Schema.
Without going into the specific details of RGB implementation, which will be covered later, an initial and fundamental definition of State is required. Simply put:
A State can be defined as a unique configuration of information or data that represents the conditions of a contract at a specific point in time.
Therefore, a Contract Operation, in general terms, represents any first creation/update of data from an old state to a new state following the rules inscribed into the contract constituting its Business Logic.
The chain of Contract Operations in RGB is the ordered path that evolves the contract data from the first contract definition, called Genesis to the Terminal State that represents the most up-to-date state at the end of the DAG of Contract Operations.
The ordering relationship between the DAGs is maintained through the commitments that anchor the client-side validated data to the Bitcoin Blockchain which, in turn, provides timestamping capabilities and source of ordering.
