webledgers/index.html at gh-pages · solidpayorg/webledgers · GitHub

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<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>Web Ledgers 0.1.4</title>
    <meta
      name="description"
      content="A specification for mapping URIs to balances on the web, enabling distributed ledger systems across platforms and protocols."
    />
    <meta
      name="keywords"
      content="web ledgers, distributed ledger, URI, balance, payments, cryptocurrency, nostr, decentralized"
    />
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  <body>
    <section id="abstract">
      <p>
        Web Ledgers provide a standardized method for mapping Uniform Resource
        Identifiers (URIs) to numerical balances on the web, enabling
        distributed ledger systems that transcend platform boundaries. This
        specification defines data models, serialization formats, and
        interoperability guidelines for creating decentralized economic systems
        using web-native identifiers.
      </p>

      <p>
        By utilizing URIs as universal identifiers, Web Ledgers enable seamless
        value transfer between heterogeneous systems including social platforms,
        blockchain networks, communication protocols, and decentralized identity
        systems. The specification supports multiple serialization formats
        (JSON) and provides extensible entry types for different use cases.
      </p>

      <p>
        This document defines the core data model, JSON Schema validation rules,
        and provides comprehensive examples demonstrating interoperability
        across platforms including Nostr, WebID, traditional web services, and
        cryptocurrency systems.
      </p>
    </section>

    <section id="sotd">
      <p>
        This document is an informal draft being discussed in the
        <a href="https://www.w3.org/community/webpayments/"
          >W3C Web Payments Community Group</a
        >. It is not a W3C Standard nor is it on the W3C Standards Track.
      </p>
      <p>
        This is a living document that may be updated, replaced, or obsoleted by
        other documents at any time. It is inappropriate to cite this document
        as other than work in progress.
      </p>
      <p>
        Comments and feedback on this specification are welcome and should be
        directed to the
        <a href="https://github.com/solidpayorg/webledgers/issues/"
          >GitHub issues</a
        >
        for this specification.
      </p>
    </section>
    <section>
      <h2>Introduction</h2>

      <p>
        The modern web consists of numerous independent platforms and services,
        each maintaining their own user accounts and value systems. Traditional
        ledgers, in their simplest form, consist of two columns: an identifier
        for an agent and their corresponding balance. Web Ledgers extend this
        concept to the web scale by utilizing [[RFC3986]] Uniform Resource
        Identifiers (URIs) as universal identifiers that transcend platform
        boundaries.
      </p>

      <p>
        This specification defines a standardized approach for representing and
        exchanging balance information across heterogeneous systems including
        social networks, blockchain platforms, communication protocols, and
        decentralized identity systems. By leveraging web standards and
        providing multiple serialization formats, Web Ledgers enable
        interoperability between previously incompatible systems.
      </p>

      <p>The Web Ledgers specification provides:</p>

      <ul>
        <li>A core data model for representing URI-to-balance mappings</li>
        <li>JSON-LD based serialization format</li>
        <li>
          Flexible amount formats supporting single or multi-currency entries
        </li>
        <li>Interoperability guidelines for cross-platform integration</li>
      </ul>

      <section id="conformance" class="informative">
        <h3>Conformance</h3>
        <p>
          As well as sections marked as non-normative, all authoring guidelines,
          diagrams, examples, and notes in this specification are non-normative.
          Everything else in this specification is normative.
        </p>
        <p>
          The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
          "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
          document are to be interpreted as described in [[RFC2119]].
        </p>
      </section>

      <section class="informative">
        <h2>Design Goals</h2>

        <p>
          Web Ledgers are a component of larger systems, such as the Linked Data
          ecosystem [[LINKED-DATA]], which have driven the design goals for this
          specification. This section summarizes the primary design goals for
          this specification.
        </p>

        <table class="simple">
          <thead>
            <tr>
              <th>Goal</th>
              <th>Description</th>
            </tr>
          </thead>

          <tbody>
            <tr>
              <td>Simplicity</td>
              <td>
                The ledger is designed to be as simple as possible. As such you
                just need two data points. The user and the balance.
              </td>
            </tr>

            <tr>
              <td>Decentralization</td>
              <td>
                The ledger should not be server specific, though it may be.
              </td>
            </tr>

            <tr>
              <td>Security</td>
              <td>
                Transmission of a ledger changes tend to be over encrypted
                channels.
              </td>
            </tr>

            <tr>
              <td>Discoverability</td>
              <td>
                It may be possible to discover more information about a URI by
                standard mechanisms of dereferencing, including, but not limited
                to HTTP.
              </td>
            </tr>

            <tr>
              <td>Interoperability</td>
              <td>
                URIs are used to provide wide interoperability with existing
                systems on the web.
              </td>
            </tr>

            <tr>
              <td>Portability</td>
              <td>
                Be system and network-independent and enable entities to use
                their digital identifiers with any system that supports Web
                Ledgers.
              </td>
            </tr>

            <tr>
              <td>Extensibility</td>
              <td>
                When possible, enable extensibility provided it does not greatly
                hinder interoperability, portability, or simplicity.
              </td>
            </tr>
          </tbody>
        </table>
      </section>
    </section>

    <section id="design" class="informative">
      <h3>Terminology</h3>

      <h3>Terminology</h3>

      <dl class="termlist">
        <dt>
          <dfn class="export" lt="web ledger|web ledgers">Web Ledger</dfn>
        </dt>
        <dd>
          A structured data format that maps URIs to numerical balance values,
          optionally including a human-readable name and description. A Web
          Ledger enables interoperability between different systems by using
          web-native identifiers.
        </dd>

        <dt><dfn class="export" lt="agent|agent">Agent</dfn></dt>
        <dd>
          An Agent is a URI that denotes a person, machine or account on the
          web.
        </dd>

        <dt><dfn class="export" lt="balance|balance">balance</dfn></dt>
        <dd>
          Each URI maps to a balance in the Web Ledger. A balance is a numerical
          value with an explicit or implicit unit of currency. If not unit is
          stated the unit MAY be taken from the popular electronic coin,
          bitcoin, and is equal to 1 satoshi.
        </dd>

        <dt><dfn class="export" lt="currency|currency">currency</dfn></dt>
        <dd>A currency is denomination of a given balance</dd>

        <dt>
          <dfn class="export" lt="ledger name|ledger names">Ledger Name</dfn>
        </dt>
        <dd>
          A human-readable string that identifies a Web Ledger. The name
          provides a friendly identifier that helps users and systems
          distinguish between different ledgers.
        </dd>

        <dt>
          <dfn class="export" lt="decentralized system|decentralized systems"
            >decentralized system</dfn
          >
        </dt>
        <dd>
          A system in which lower level components operate on local information
          to accomplish global goals. For example, an ant colony is a
          decentralized system as there is no central control determining when
          food must be collected or how new tunnels should be excavated.
        </dd>
      </dl>
    </section>

    <section id="Data Model" class="Data Model">
      <h2>Data Model</h2>

      The Web Ledgers data model uses JSON-LD as its primary serialization
      format, designed to have varying layers of complexity depending on the use
      case.

      <h3>JSON / JSON-LD</h3>

      <p>
        A structured JSON format for a ledger consists of an entries array with
        metadata and typed entries. The ledger can include a human-readable name
        and description to provide context about its purpose and contents. The
        amount field supports both simple string values (for single currency)
        and arrays of currency objects (for multi-currency entries).
      </p>
      <pre
        class="example highlight"
        title="Example of structured JSON-based web ledger"
      >
 {
   "@context": "https://w3id.org/webledgers",
   "type": "WebLedger",
   "id": "https://example.com/ledger/1",
   "name": "WebLedgers Example",
   "description": "A ledger tracking balances across multiple platforms",
   "created": 1705316200,
   "updated": 1705316200,
   "defaultCurrency": "satoshi",
   "entries": [
     {
       "type": "Entry",
       "url": "did:nostr:de7ecd1e2976a6adb2ffa5f4db81a7d812c8bb6698aa00dcf1e76adb55efd645",
       "amount": "132500"
     },
     {
       "type": "Entry",
       "url": "https://www.w3.org/People/Berners-Lee/card#i",
       "amount": "100000"
     }
   ]
 }
    </pre
      >

      <h4>Entry Variations</h4>
      <p>
        All entries use the same "Entry" type but can have different properties
        depending on their purpose. The amount field can be either a simple
        string (for single currency in default denomination) or an array of
        currency objects (for multi-currency entries):
      </p>
      <pre class="example highlight" title="Different entry variations">
 {
   "@context": "https://w3id.org/webledgers",
   "type": "WebLedger",
   "id": "https://gaming.example.com/ledger/tournament",
   "name": "Gaming Tournament Rewards",
   "description": "Prize distribution ledger for esports tournament participants",
   "defaultCurrency": "satoshi",
   "entries": [
     {
       "type": "Entry",
       "url": "did:nostr:de7ecd1e2976a6adb2ffa5f4db81a7d812c8bb6698aa00dcf1e76adb55efd645",
       "amount": "132500"
     },
     {
       "type": "Entry",
       "url": "https://www.w3.org/People/Berners-Lee/card#i",
       "amount": [
         {"currency": "satoshi", "value": "50000"},
         {"currency": "USD", "value": "25.00"}
       ]
     },
     {
       "type": "Entry",
       "url": "urn:voucher:1234567890abcdef",
       "amount": [
         {"currency": "points", "value": "100"}
       ]
     }
   ]
 }
    </pre
      >

      <h4>Amount Serialization Rules</h4>
      <p>
        The amount field supports flexible serialization based on the currency
        context:
      </p>
      <ul>
        <li>
          <strong>Simple string format:</strong> Use when there is exactly one
          balance in the ledger's defaultCurrency. Example:
          <code>"amount": "100000"</code>
        </li>
        <li>
          <strong>Array format:</strong> Use when there are multiple currencies
          or when the currency differs from the defaultCurrency. Example:
          <code>"amount": [{"currency": "USD", "value": "25.00"}]</code>
        </li>
      </ul>

      <h3>Named Ledger Use Cases</h3>
      <p>
        Web Ledgers can use descriptive names to clarify their purpose and
        context:
      </p>

      <h4>Community Reputation System</h4>
      <pre class="example highlight" title="Community reputation ledger">
{
  "@context": "https://w3id.org/webledgers",
  "type": "WebLedger",
  "id": "https://community.example.com/reputation",
  "name": "Developer Community Reputation",
  "description": "Reputation scores for open source contributors based on code contributions and peer reviews",
  "defaultCurrency": "reputation-points",
  "entries": [
    {
      "type": "Entry",
      "url": "https://github.com/alice-dev#this",
      "amount": "2750"
    }
  ]
}
       </pre
      >

      <h4>Educational Achievement Tracking</h4>
      <pre class="example highlight" title="Educational achievement ledger">
{
  "@context": "https://w3id.org/webledgers",
  "type": "WebLedger",
  "id": "https://university.example.edu/course-credits",
  "name": "Computer Science Course Credits",
  "description": "Academic credit tracking for CS degree program students",
  "defaultCurrency": "credit-hours",
  "entries": [
    {
      "type": "Entry",
      "url": "mailto:student@university.example.edu",
      "amount": "120"
    }
  ]
}
       </pre
      >
    </section>

    <section id="security-considerations">
      <h2>Security Considerations</h2>

      <p>
        Web Ledgers implementations SHOULD consider the following security
        aspects:
      </p>

      <section>
        <h3>Authentication and Authorization</h3>
        <p>
          Implementations SHOULD provide mechanisms to authenticate ledger
          updates and authorize balance modifications. Without proper
          authentication, malicious actors could manipulate balances or create
          fraudulent entries.
        </p>
        <p>Recommended approaches include:</p>
        <ul>
          <li>Digital signatures using cryptographic key pairs</li>
          <li>OAuth 2.0 or similar authentication protocols</li>
          <li>Multi-signature schemes for high-value transactions</li>
        </ul>
      </section>

      <section>
        <h3>Data Integrity</h3>
        <p>
          Implementations SHOULD implement mechanisms to ensure data integrity
          and prevent tampering. This includes:
        </p>
        <ul>
          <li>Cryptographic hashing of ledger entries</li>
          <li>Merkle tree structures for efficient verification</li>
          <li>Timestamp validation to prevent replay attacks</li>
        </ul>
      </section>

      <section>
        <h3>Transport Security</h3>
        <p>
          All ledger data transmission MUST occur over secure channels
          (HTTPS/TLS) to prevent man-in-the-middle attacks and ensure
          confidentiality.
        </p>
      </section>
    </section>

    <section id="privacy-considerations">
      <h2>Privacy Considerations</h2>

      <p>
        Web Ledgers may contain sensitive financial information. Implementations
        SHOULD consider the following privacy aspects:
      </p>

      <section>
        <h3>Data Minimization</h3>
        <p>
          Implementations SHOULD only store and transmit the minimum amount of
          information necessary for ledger functionality. Sensitive metadata
          should be avoided unless essential.
        </p>
      </section>

      <section>
        <h3>URI Privacy</h3>
        <p>
          URIs used as identifiers may reveal personal information.
          Implementations SHOULD:
        </p>
        <ul>
          <li>Support pseudonymous identifiers where possible</li>
          <li>Provide mechanisms for identifier rotation</li>
          <li>Clearly document any privacy implications of URI schemes</li>
        </ul>
      </section>

      <section>
        <h3>Access Control</h3>
        <p>
          Implementations MUST provide appropriate access controls to prevent
          unauthorized access to balance information. This includes:
        </p>
        <ul>
          <li>Role-based access control (RBAC)</li>
          <li>Fine-grained permissions for different operations</li>
          <li>Audit logging for compliance and monitoring</li>
        </ul>
      </section>
    </section>

    <section id="implementations" class="informative">
      <h2>Implementations</h2>

      <p>
        This section is informative and provides guidance for implementers of
        Web Ledgers systems.
      </p>

      <section>
        <h3>Reference Implementation</h3>
        <p>
          A reference implementation is available at
          <a href="https://github.com/solidpayorg/webledgers-reference"
            >https://github.com/solidpayorg/webledgers-reference</a
          >.
        </p>
      </section>

      <section>
        <h3>Known Implementations</h3>
        <p>The following implementations are known to support Web Ledgers:</p>
        <ul>
          <li>
            SolidPay Ledger Service - Production implementation supporting
            multiple URI schemes
          </li>
          <li>
            Nostr Ledger Extension - Experimental implementation for Nostr
            protocol
          </li>
        </ul>
      </section>
    </section>

    <section id="examples" class="appendix informative">
      <h2>Examples</h2>

      <h3>Decentralized Identifiers</h3>

      <h4>Nostr DID</h4>
      <p>
        Nostr public keys represented as DIDs for decentralized social
        networking.
      </p>
      <pre class="example highlight" title="Nostr DID ledger entry">
{
  "type": "Entry",
  "url": "did:nostr:de7ecd1e2976a6adb2ffa5f4db81a7d812c8bb6698aa00dcf1e76adb55efd645",
  "amount": "132500"
}
    </pre
      >

      <h4>WebID</h4>
      <p>A WebID representing a person's web identity.</p>
      <pre class="example highlight" title="WebID ledger entry">
{
  "type": "Entry",
  "url": "https://www.w3.org/People/Berners-Lee/card#i",
  "amount": "100000"
}
    </pre
      >

      <h3>Social Platforms</h3>

      <h4>GitHub</h4>
      <p>The popular git service platform.</p>
      <pre class="example highlight" title="GitHub ledger entry">
{
  "type": "Entry",
  "url": "https://github.com/solid-pay#this",
  "amount": "75000"
}
    </pre
      >

      <h4>Twitter/X</h4>
      <p>The microblogging service.</p>
      <pre class="example highlight" title="Twitter ledger entry">
{
  "type": "Entry",
  "url": "https://x.com/user#this",
  "amount": "50000"
}
    </pre
      >

      <h4>YouTube</h4>
      <p>The video sharing platform.</p>
      <pre class="example highlight" title="YouTube ledger entry">
{
  "type": "Entry",
  "url": "https://www.youtube.com/channel/UCabcdef1234567890#this",
  "amount": "25000"
}
    </pre
      >

      <h3>Communication Protocols</h3>

      <h4>Email</h4>
      <p>Traditional email addresses as identifiers.</p>
      <pre class="example highlight" title="Email ledger entry">
{
  "type": "Entry",
  "url": "mailto:timbl@w3.org",
  "amount": "15000"
}
    </pre
      >

      <h4>Mobile Phone</h4>
      <p>Phone numbers as global identifiers.</p>
      <pre class="example highlight" title="Mobile ledger entry">
{
  "type": "Entry",
  "url": "tel:+15550909090",
  "amount": "10000"
}
    </pre
      >

      <h3>Cryptocurrency & Blockchain</h3>

      <h4>Bitcoin Address</h4>
      <p>Bitcoin addresses as payment identifiers.</p>
      <pre class="example highlight" title="Bitcoin ledger entry">
{
  "type": "Entry",
  "url": "bitcoin:1Kr6QSydW9bFQG1mXiPNNu6WpJGmUa9i1g",
  "amount": "2100000"
}
    </pre
      >

      <h4>Transaction Outputs</h4>
      <p>Bitcoin transaction outputs (UTXOs) as specific balance holders.</p>
      <pre class="example highlight" title="Transaction output ledger entry">
{
  "type": "Entry",
  "url": "txo:btc:f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16:0",
  "amount": "5000000000"
}
    </pre
      >

      <h3>Vouchers & Tokens</h3>

      <h4>Web Voucher</h4>
      <p>Digital vouchers following the webvoucher specification.</p>
      <pre class="example highlight" title="Voucher ledger entry">
{
  "type": "Entry",
  "url": "urn:voucher:1234567890abcdef",
  "amount": "25000"
}
    </pre
      >

      <h3>Complete Ledger Example</h3>
      <p>
        A complete ledger with multiple entry variations demonstrating the full
        data model with descriptive naming for clarity, including both simple
        string amounts and multi-currency arrays.
      </p>
      <pre class="example highlight" title="Complete multi-platform ledger">
 {
   "@context": "https://w3id.org/webledgers",
   "type": "WebLedger",
   "id": "https://example.com/ledger/global",
   "name": "Universal Web Credits",
   "description": "Cross-platform ledger demonstrating interoperability between social networks, blockchain systems, and communication protocols",
   "created": 1705276800,
   "updated": 1705316200,
   "defaultCurrency": "satoshi",
  "entries": [
    {
      "type": "Entry",
      "url": "did:nostr:de7ecd1e2976a6adb2ffa5f4db81a7d812c8bb6698aa00dcf1e76adb55efd645",
      "amount": "132500"
    },
    {
      "type": "Entry",
      "url": "https://www.w3.org/People/Berners-Lee/card#i",
      "amount": [
        {"currency": "satoshi", "value": "100000"},
        {"currency": "USD", "value": "50.00"},
        {"currency": "reputation-points", "value": "500"}
      ]
    },
    {
      "type": "Entry",
      "url": "https://github.com/solid-pay#this",
      "amount": "75000"
    },
    {
      "type": "Entry",
      "url": "mailto:timbl@w3.org",
      "amount": [
        {"currency": "EUR", "value": "12.50"}
      ]
    },
    {
      "type": "Entry",
      "url": "urn:voucher:1234567890abcdef",
      "amount": "25000"
    }
  ]
}
    </pre
      >
    </section>

    <section id="acknowledgements" class="appendix informative">
      <h2>Acknowledgements</h2>

      <p>
        The editor would like to thank the
        <a href="https://www.w3.org/community/webpayments/"
          >W3C Web Payments Community Group</a
        >
        for their support and feedback during the development of this
        specification.
      </p>

      <p>
        Special thanks to the following individuals and organizations for their
        contributions, feedback, and implementation efforts:
      </p>

      <ul>
        <li>The W3C Web Payments Community Group participants</li>
        <li>The Nostr protocol development community</li>
        <li>The Solid project community</li>
        <li>Contributors to the SolidPay project</li>
      </ul>

      <p>
        This specification builds upon the foundational work of the World Wide
        Web Consortium, particularly the URI specification [[RFC3986]] and the
        JSON-LD specification [[JSON-LD11]].
      </p>
    </section>
  </body>
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