Statur

Table of Contents

• Overview
• Non-Transferable (Soulbound) Tokens
  • Soulbound Token Flow
• Dynamic Content NFTs
• Reputational Model
  • End-to-End Reputation Flow
  • Entering the Reputation Contract
  • Updating a User's Reputation
  • Off-Chain Reputation Database
  • Reputation Scoring
• List of Reputation Metrics

Overview

This documentation offers a comprehensive overview of Statur, also known as the Self-Sovereign Pseudonymous Reputational Model, and its components, which include Non-Transferable (Soulbound) Tokens and Dynamic Content NFTs.

The self-sovereign pseudonymous reputational model is a revolutionary solution that allows projects to gather, utilize, and disseminate information about their pseudonymous users, while preserving user data sovereignty. This concept employs two cutting-edge technologies: non-transferable (soulbound) tokens and dynamic content NFTs.

Non-Transferable (Soulbound) Tokens

Soulbound tokens are unique assets that are non-transferable, opening up a broad spectrum of applications. These tokens facilitate the recording of a "soul point" on a user's wallet, which can either be endorsed or rejected by the user.

Soulbound Token Flow

1. A Cardano-based project records a soul point on a user’s wallet.
2. A “basic” soul point is stored on-chain as a UTXO containing pertinent data.
3. The user can endorse the basic soul point or reject it.
4. If the user opts to discard the soul point, it is effectively removed from the chain.
5. If the user accepts the soul point, it is assigned a new “endorsed” signature.
6. The user retains the ability to reconsider at any moment and burn the soul point.

Dynamic Content NFTs

NFTs are typically used to hold unique, static information on-chain. However, the capacity to dynamically update this data off-chain, without compromising the essential decentralization aspect, is highly desirable.

With our unique decentralized data storage network, an NFT can serve as a pointer to a file. The contents of this file are subject to change by users who hold certain access rights on the storage network.

Reputational Model

By integrating the eUXTO model with our decentralized storage mechanisms, we can accumulate reputational information about a user's wallet and store it on our decentralized storage network. The on-chain file index tied to a user's wallet functions as a pointer to data that projects can dynamically update with information regarding the user's participation and behavior.

End-to-End Reputation Flow

General Overview

The reputation contract system offers a straightforward yet effective mechanism for providing on-chain, verifiable reputation data. Users join the reputation system by entering into the smart contracts. A user's reputation data is then updated in real time using an off-chain database. Every user's on-chain data is periodically updated automatically using the off-chain data.

The goal of the system is to provide users with a cost-efficient and scalable method for storing and updating their reputation data. We opt for constant-cost and highly parallelizable smart contracts over variable costs and rigid solutions, resulting in a unique blend of on-chain and off-chain protocols. The final product is a system for storing reputations on-chain while updating them in real-time via an off-chain database.

Entering the Reputation Contract

Each user will have a single UTxO inside the reputation contract, holding a special and soulbound NFT. The token may not leave the contract due to validator logic. A user may remove their UTxO from the reputation contract at any time; however, this will result in the burning of the soulbound token. The token serves as a unique identifier of a user's reputation, which is stored on-chain as a hash in the datum. The full reputation data is maintained in an off-chain database to support large data structures.

Users will contribute Lovelace to a fee contract for periodic updates. A special batcher uses the off-chain database and fee contract to perform reputation updates efficiently through transaction chaining.

Updating a User's Reputation

Reputation data is stored in an off-chain database. Storing complex data on-chain is limited by blockchain protocol constraints, so we only store a hash on-chain. Updates involve changing the hash of the off-chain data structure in a verifiable and reproducible way. These updates are efficient and allow for batch transactions. Users may also trigger updates independently if desired.

Off-Chain Reputation Database

The off-chain reputation database operates as an account-based state machine. Each update (or transition) to a user's reputation is signed by an authorized party and stored in a linear history. This ensures full traceability and allows users to reproduce and verify their reputation state independently.

Users can selectively authorize projects to update their data. For example, a user in the Iagon ecosystem may allow Iagon to track and update their data. Other projects cannot update a user's reputation without explicit permission. Thus, reputation is user-centric and ecosystem-specific.

The on-chain reputation data is stored as a Blake2b-256 hash of the canonical form of the user's reputation data. This allows for on-chain verification of off-chain data by reconstructing the hash step by step.

Reputation Scoring

Each user's reputation is assigned a score based on predefined metrics. This score is retrieved from the off-chain database and used in real time. While the full data is off-chain, the on-chain hash ensures transparency and verifiability.

List of Reputation Metrics

The following table outlines the initial set of metrics proposed for evaluating user and node reputation within the Cardano ecosystem, specifically aligned with Iagon’s infrastructure and decentralized storage operations.

Metric Name	Description
Read Speed	Average time taken by a node to retrieve stored data.
Write Speed	Average time required to write data to the node.
Download Speed	Download throughput measured during user data retrieval.
Upload Speed	Upload throughput measured during data storage to the node.
Uptime	Percentage of time the node remains online and available.
Pledge Amount	Total ADA pledged by the node operator.
Delegation Amount	Total ADA delegated by users to the node.
Number of Delegators	Number of individual delegators to the node.
Node Size	Total storage capacity available on the node.
Minimum Delegation	Minimum amount of ADA accepted by the node.
Maximum Delegation	Maximum amount of ADA accepted by the node.
Margin Percentage	Percentage of rewards taken as margin by the node operator.

These metrics form the core of the quantitative scoring system used in Statur. They are designed to measure contribution, reliability, and performance in a standardized and transparent way.

Note:
This list is part of the first phase of development and may be revised or extended as the system evolves. Additional metrics may be introduced based on community feedback, new use cases, and technical requirements.